Solderman Basic Electronics

Basic Electronics, Practical Electronic Projects, Learning Circuit design, Electrical Fundamentals. Edutainment and Interactive Examples.

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Monday, December 24, 2018

Design Notes - Power Electronics - 02

Power Supplies and SMPS, Transformers, Drive circuits for Motors, Heaters and Solenoids are all Power Electronics. Thyristors, Mosfets and High Power Transistors are important components used in these circuits.

Tek Power Supply Facia - Observe the user friendly interface design.

Tek Power supply

Power Design Points to note - delabs
  • Foldback circuits in the form of constant current or voltage can protect a Power Circuit from overload. eg. Charger.
  • Air gap in inductor core prevents saturation of the Magnetics, it must be made like that when required. eg. Choke.
  • High power equipment should have a soft start, so that fuses dont blow on start, inrush can cause damage to parts.
  • Caps can be put in series to double voltage withstand capability, when we put el-caps in series they have to be identical in value. put caps in parallel to increase the cap uF value and it also lowers ESR which is equivalent series resistance, this is good when filtering in SMPS. Two el-caps with the negatives of both connected and the positive terminals serving as the two terminals will give a non-polar cap, used in crossover networks.
  • When smps has to work at 100Khz or more, the primary of transformer must have multiple strands, and secondary can be a copper flat ribbon. this is due to skin effect, as high frequency current flows on surface of conductor.
  • MOSFET needs a turn on pulse and a turn off pulse as gate capacitance is huge.
  • Do not club Heatsinks unless the heatsink is very big or the clubbed components form a part of a current sharing set. If you club say two TO220 devices one dissipating 10W with a 2 Watt heating device, you may reduce reliability of the 2W device. Then clubbing parallel current sharing devices on one heatsink may be a good idea as it may reduce thermal runaway, also parallel power transistors should each have 0.1E in emitter path, this also can force load sharing on lazy devices.
  • Test a mosfet, charge the gate with the DMM in diode mode, then there is a short between source and drain.
  • Snubbers consisting of R-C should be used across switches, relay contacts, MOSFETS when switching inductive loads, this will absorb the spike and save the device.
  • Transformers used in SMPS could be split bobbin for product safety, and transformers should be resin impregnated, hazard may arise when using a badly made product.
  • In a SMPS which is not earthed the floating (unconnected) earth terminal will give a slight shock due to the two Y caps connected to earth from phase and neutral.
  • Power mosfets, transistors or IGBT's should be electrically isolated very well from heatsink with alumina, mica or silpad. It could withstand 2KV -5KV DC, related to product safety. Also these heatsinks should not be earthed but floating, do not fix to the metal chassis for maximum safety.
delabs design notes from the 90s

Instrumentation and Automation - 02

In Test and Measurement and Industrial Process Control a common factor is instrumentation. The measuring aspect is common to both. T&M instruments are used in Testing, Research,Automated Testing, Troubleshooting and Servicing.

Instrumentation and Automation - 02

Process control Instruments are used in Production Lines made of Machines in a Factory. It could be Counters and Timers used for Textile or Steel Industry. It can also be Temperature and Pressure Controllers used in Oil Refining or Food Processing.

So you see a difference. We have handheld Test Instruments like DMM and Scope and We have Handheld Instruments for Gas Monitoring or Humidity too. In automated testings we have rack mount test instruments. In Control panels we have Rail Mount carrying DIN standard Instruments.
  • On-Off controls or level trip relays can oscillate if hysteresis dead band is very small or absent.
  • Hysteresis is like on at 300 off at 304 like in heaters or air conditioners. If you on-off at sharp 300 there is a chatter or oscillation. This is called dead-band in temperature control. In above example 304-300=4 is the dead-band.
  • LF356, TLO71 and CA3140 are FET input Op-Amps, the bias is in pA, The caps for sample hold with these opamps are low leakage ones.10uF tantalum for long time, low resolution data. Long hold times with 12 bit data (analog) use 1uF plastic multilayer and clean-IPA + coat PCB with epoxy.
  • Design the product in such a way that neither the pot terminals or pot switch is used for mains voltage, instead use the pot switch or variable resistance for signaling and the mains can be switched with Relay or Thyristor.
  • If you need a 10.00K resistor 0.1% and you only have 1% in the market, you can trim lower values to higher values by removing the paint of the resistor and scratching the black metal film till you get the desired value. (this is only for testing or prototype development, R&D, not for manufacturing).
  • 7107 and 7135 of Intersil can be tested in-circuit, check Vref for 100mV or 1V reference, then short Vin and Vref the reading should be 1000 counts for 7107 and 10000 counts for 7135. ground plane should be good, no ground loops, PCB only glass epoxy and low leakage caps to be used, then reading will be stable, use some coating on soldered PCB.
  • An electrically Noisy environment can be simulated with a hair drier, or hot air blower. Another way Looping the NC (normally closed) contacts of a 230V Electrical Contacter-Relay can make it oscillate, this makes a lot of Sound and more important is the Electrical noise rich in EMI-RFI. This helps basic testing of timers, counters, uP, uC and embedded systems as they may malfunction in noisy environment.
  • A Single Pole 12V 100mA relay in a feedback loop, with its contacts, can make a Electrical or Electromechanical Oscillator. This can test your ground loops and digital circuit decoupling caps. It simulates power spikes which may reset some counters.
  • When a Machine with many stages or even an entire production line has to be automated, a PLC system is easiest to configure. It has digital inputs for limit switches and proximity sensors, it has analog inputs for any other parameter sensor. The PLC output modules can drive Electrical Contactor circuits with 230V Signal or 4-20 mA for an AC drive. The tacho-generator voltage feedback or pulses feedback from a motor can be fed to PLC inputs too.
  • Automation is used to enhance the quality and quantity of the product, also where there is danger to operators or workers. This moves the worker up, into the maintenance and management of materials, machines and systems.
  • Industrial Automation is essential to enhance the manufacturing worker to deliver consistent, repeatable and timely delivery of products. Absence of automation makes quality and deliveries unpredictable and stresses worker on monotonous jobs. When the worker is creatively employed with his machine on automation, it is the best scenario.

Solderman Talks 1702 AD
"Over-Automation is an utopia which is incorrect. This is because if you have no workers in any factory, there are no consumers in that city. No consumers means no sales of goods, no building of houses, no buying of automobiles. All strata of People correctly employed, reasonably paid, seeds consumerism, promotes the economy and markets. Automate everything, economy grinds to an halt."

- Solderman Talks 1702 AD

Wednesday, December 12, 2018

Theory and Tutors in Electronics

Learning electronics in theory by studying books is the conventional way, this method may help in History and Maths. Maths needs a paper and pencil for practicals and history needs a well equipped Library. In these modern times, the web has made access to wide range of learning information easy, which is true Knowledge Empowerment. The greatest gift a Child can get from the Parents or School, is Knowledge.

Electronics Theory and Tutorials  

As an Electronics Engineer i had always needed data sheets and application notes. The web makes these documents not only accessible to all, but searchable too.

Process Control Instruments

These are some instruments i manufactured when i used to run my own industrial automation business.

Theory and Tutors in Electronics

Now many Virtual Electronics Workbench Software and Interactive Tutors are available, these aid learning. We have to design, build and apply some electronic ideas in 3D Hardware, for complimenting the Book, Academic or Web learning. Practical and Theoretical study in electronics has to be in Tandem, this is possible only when Industry works with Universities to create real talent and skills in students. The applied technology is evolving, hence the academic education must be relevant when the student gets into his first job.
Solderman Talks 1702 AD
"when you solder the windows should be opened, cross ventilation must be good, because the fumes are not very good for health. After you finish wash your hands with soap, as lead is poisonous or toxic"

- Solderman Talks 1702 AD

Friday, November 23, 2018

Accelerometers in Electronics

An accelerometer is a device that measures non-gravitational accelerations. These are accelerations produced by mechanically accelerating the accelerometer via its casing. Accelerometers can be used to measure vehicle acceleration.

Accelerometers can be used to measure vibration on cars, machines, buildings, process control systems and safety installations. They can also be used to measure seismic activity, inclination, machine vibration, dynamic distance and speed with or without the influence of gravity. - Accelerometer Wikipedia

Accelerometers in Electronics

MMA7260Q is a 3-axis accelerometer  from Freescale Semiconductor. This accelerometer can be used with an extension Library Mma7260q which simplifies some initialization values and tilt detection.

ADXL105 Lower-Noise Wider-Bandwidth Accelerometer - The ADXL105, a near-ideal kind of vibration sensor, eliminates significant problems with existing vibration sensors, such as piezoelectric and bulk capacitive sensors. Primary benefits derive from much lower cost, stable sensitivity as a function of frequency and temperature, ruggedness, and ease of use. Besides machine health and condition monitoring, it is particularly well suited for noise and vibration cancellation applications.

A beginner's guide to accelerometers - By measuring the amount of static acceleration due to gravity, you can find out the angle the device is tilted at with respect to the earth. By sensing the amount of dynamic acceleration, you can analyze the way the device is moving.

Society of Robots' tilt to servo control app - How does it work? Inside an accelerator MEMS device are tiny micro-structures that bend due to momentum and gravity. When it experiences any form of acceleration, these tiny structures bend by an equivelent amount which can be electrically detected

David T.'s motor balancing experiments - Using an oscilloscope to measure AC vibration signals generated by an accelerometer (from Dimension Engineering).

Circuit Builder with Oscilloscope - Physlets

Simulates AC and DC circuits. Created by by Toon Van Hoecke at the Universiteit Gent. Try out small circuits and see response in Meters and Scope. Using the Java Applet Power.

Install the latest Java jre and use the IE browser. In Control Panel Java-Security add a site exception Then you can see the simulations. (2017 win 10 )

Physlets, Physics Applets,

Physlets are simple.  The graphics are simple; each Physlet is designed to deal with only one facet of physical phenomena, and does not incorporate very much in the way of data analysis.  This keeps Physlets relatively small—easing downloading problems over slow network connections—and removes details that could be more distracting than helpful.

Circuit Builder with Oscilloscope - Physlets

Circuitbuilder simulates AC and DC circuits.  It was written by by Toon Van Hoecke at the Universiteit Gent.  Circuit Builder can be used in interactive mode (see above) or it can be scripted using JavaScript (see the demo pages). In order for scripting to work, Circuit Builder requires a Java 1.1 capable browser with JavaScript to Java scripting capability.

Friday, November 16, 2018

Transistor Beta and Vce Tester

This was a Beta Hfe and Vce Measuring Instrument used in Incoming Inspection of Power Transistors made by me 16 years back.

Transistor Beta Tester

Custom Built Test Instruments

I designed and built many custom "engineered" Test Instruments. They were not prefect, as only one or two were fabricated. That means it will be costly to produce such instruments. It is just like tooling, you have to make some numbers to recover costs, or price it very high to compensate for the wastages and iterations.

When making custom equipment, you have to have an extended service agreement like 5 years. Also request a minimum order of at least 5. Make your R&D and Inventory Modular. That way it is profitable and some money available for reinvestment on instruments and Equipment for calibration and quality.

Wednesday, October 24, 2018

System-on-Chip - SoC - IP

When a product has to be made small, the board real estate is limited or it has to be manufactured in large numbers.... SoC is the Answer. A Microprocessor evolved into a Microcontroller by packing many external chips into one chip. Now uC Card along with the other blocks like A-D, Port Drivers, Networking elements, Display Driver and other peripherals can be packed into one chip.

Some Power Supply and RF blocks cannot be easily added inside as they have a silicon processing more specific to their applications. Laser trimmed Instrumentation Op-Amps, high accuracy resistor arrays, high value capacitors, magnetics and supporting chips are placed outside on the PCB.

The SOC can pack Digital Chips, Memory, A/D, D/A converters, uC, RAM and Custom programmable areas. For more specialized communications, analog and power requirements; Special SoC types can tackle RF and Power management within a chip because of proprietary silicon processing expertise.

System on a chip - Wiki

"A system on a chip or system on chip (SoC or SOC) is an integrated circuit (IC) that integrates all components of a computer or other electronic system into a single chip. It may contain digital, analog, mixed-signal, and often radio-frequency functions—all on a single chip substrate. A typical application is in the area of embedded systems."

System-on-Chip - SoC - IP

Programmable SoC offers an alternative to custom ASIC as you can make different products from the same chip, yet make products that are portable and low power. The software, pcb, user interface and support components has to be redesigned for every unique product. Many standard IPs are available for Design and Reuse.

Saturday, October 20, 2018

Design Notes - Schematic and PCB - 04

PCB Thermal Design Care for Analog Circuit Stability - If you have a hot power chip near a DC analog circuit, the values will drift, take time to stabilize, this happens even if you use 1% MFR 100ppm. The impact is more if the heatsink is not used and vents and coolers are absent,

So in a PCB keep distance between heating power circuits and sensitive analog circuits, some times PCB tracks will carry heat to the Analog area, Hence keep sensitive analog circuits as plugin modules.

Design Notes - Schematic and PCB - 04

When you make a PCB try to orient all ICs in one direction, so also all diode and cap polarities, then it is easy to populate the parts, easy to verify and troubleshoot for production and testing.
    High Frequency and RF Design of PCB
    • Sharp bends in PCB tracks or wires will radiate away the RF energy, so do not have hairpin bends.
    • RF or near RF multilayer PCB have 2 layers as ground plane and tracks in the layer in between, Faraday cage.
    •  Electronic RF Product or System Design like  Communication Products.. Important rule "the first rule of connectors is that the best connector is no connector at all...". In RF the connectors and their placement needs extra care. At a frequency of 1 GHz, a short PCB track can become an Antenna !
    Schematic Design Basics
    • When we draw circuits we have to keep in mind the readability, the circuit should be laid out, according to the signal flow, the input output ports shown in the periphery of circuit.
    • Drawing a neat circuit diagram will ensure a better design, lesser parts means greater reliability, simple solutions.
      A well-drawn schematic makes it easy to understand how a circuit works and aids in troubleshooting; a poor schematic only creates confusion.
        Product Design Mockup and Prototypes
        • Make a 3D mockup of the final product, both the box and the PCB with components before PCB done.
        • The product with the PCbs, transformer and other panel components should fit in the box it was intended for, or the cabinet that was designed for the Product. To make sure make a Mock-up Product - 3D and display. Even if you have all documents and drawings in place.
        • Make sure of IC pin numbers, size and packages and indicate in circuit like 40 pin dip before going to PCB. Also check every EDA symbol in your software with the company datasheet to make double sure.
        • Do not mix mechanical and electrical connections, these leads to failures and frequent need of repairs and service. this is a rule, more so for power connectors.
        • Strain relief prevents mechanical stress from reaching the connector joints/spring metal. The wire terminations are also cushioned by strain relief.
        • The PCB and Product Engineering should ensure that the mechanical stress or load is not a job/function/role of the connector. At higher currents a small contact resistance can generate a lot of heat, worsening the contact further, similar to thermal runaway of Power Transistors.
        • When using a double or multi layer pcb make one layer a ground plane, all decoupling caps ground linked to it.
        • Reinforce copper tracks on PCB with a copper wire when it needs to carry more current, tinning may improve a bit.

        Friday, October 05, 2018

        Production Notes - Prototype Fabrication - 03

        Prototype Fabrication and Pilot Production are the first stages of a design concept taking a real tangible form. The transition from R&D to Manufacturing Engineering happens here.

        alpha-numeric LCD based on the twisted nematic field-effect

        Early prototype of an alpha-numeric LCD based on the twisted nematic field-effect as realized in the laboratories of the Central Research Laboratories of F. Hoffmann-La Roche Ltd. by Martin Schadt and Wolfgang Helfrich, photo by courtesy of M. Schadt.

        Sometimes a component can be defective, may not be what it is labeled or may be of a wrong value. In manufacturing 100% incoming inspection of components can catch these errors, Before Assembly of prototypes just test all passive and active components with a DMM and put all ICs in bases, then troubleshooting is easy.
        • When you make your prototype check diode and el-cap polarity, check pin 1 of chips and connectors, resistor values, dry solder and loose contacts, hairline cuts or shorts, e-b-c etc. of Transistors, FETs and thyristors.
        • Observe color code in wires. positive is red and negative is black and green is earth.
        • When you are soldering or cutting leads, room should have cross ventilation, protective glasses for eyes and a good stand.
        • When using a sharp blade the cutting stroke must move away from you and make sure nobody is close, Wear protective or even plain glasses, If you use a blade with the stroke moving towards your body it will cut badly.
        • Power tools and machinery must be used only after exhaustive training and with safety precautions. The power tools used carelessly and wrongly can cause an injury which will last a lifetime or may even handicap you.
        • Have a lathe lamp or table lamp with a 40W edison-filament lamp (ordinary bulb) on your workbench.
        • Have an antistatic mat on the work or test table, if you cannot afford or get it then get a large aluminum sheet, laminate it with an insulating polycarbonate sheet and earth the metal plate with two 1M resistors in series.
        • Use thin multi strand teflon wires for your jumpers within a PCB, these are not damaged by your iron too.
        • Silicone shrink sleeves can withstand high temperature and use this in your work to make it safer and neat.
        • When you make a connection with a wire you need mechanical strain relief or on use connection will open.

        Soldering and Desoldering Tips

        Use the soldering iron as a heat transfer tool, heat the junction of the lead of the component and the copper pad on pcb then touch the hot junction with a flux cored soldering lead wire, it should melt and form a concave shining joint.

        If air bubbles are formed or you see dull convex joints, then it means you have a dry solder and bad contact. Leads of old components due to exposure to moisture, brine or sunshine will corrode, store them well cool-dry-clean-air. Anyway scratch them with a blade and solder them with extra flux.

        When you are desoldering a double sided pcb, use a desoldering pump or desoldering wick. Heat a joint to be desoldered and then quickly tap it hard on the table, the molten lead will fall off.

        delabs Notes from 90s

        Read More

        Soldering is to electronics what stitching is to clothes. If you are good at soldering then you have come half the way of mastering robot building. The only way you can achieve this is through ‘Practice’ alone. Remember, soldering is an ART and not a mere technique.

        Thursday, July 26, 2018

        Learning Science to Promote Scientific Thinking

        Here are some resources of Science, i found useful. Latest news on science, technology, hard science subjects of physics, space and earth science, electronics, nanotechnology and technology in general.

        Museums are virtual Universities. 3D Scaled Interactive Scientific and Engineering Demonstrations in Tech Museums Inspire, Educate and Train many students on Science and Technology Subjects.

        Learning Science to Promote Scientific Thinking

        Such Live Interactive Demonstrations may be very useful for Maths and Economics as well. These are Subtle and Complex Sciences which need Gross Manifests or Exhibits to help youngsters grasp Ideas and Concepts easily.

        PhysOrg - science and tech news
        Publishing around 100 articles every business day, PhysOrg offers the most comprehensive sci-tech news coverage on the web. PhysOrg exclusive feature stories are original and not found elsewhere on the web.

        Multimedia Physics - SchulPhysik
        Physics and Physlets. Astronomy - planet, space weather, cosmos. Mathematics - algebra to statistics. Optics and electrical. Geophysics, Energy, Galileo.

        Mike's Electric Stuff is an Online Electrical Vintage Tour, back in time.

        Flinn Scientific - Science Activities - Sells educational science supplies. Site has especially useful information on lab safety and lab design.  Physical Science Activities - Exciting experiments which illustrate important scientific concepts and are exciting for both you and your students

        National Science Digital Library - NSDL was established by the National Science Foundation (NSF) in 2000 as an online library which directs users to exemplary resources for science, technology, engineering, and mathematics (STEM) education and research.

        Wednesday, July 18, 2018

        Electrochemistry Encyclopedia

        This site contains popular-science style articles describing many aspects of electrochemistry. New articles are added at irregular intervals, and all articles are periodically updated as recent developments occur in the field.

        Electrochemistry Encyclopedia
        • Anodizing - Robert S Alwitt
        • Brine electrolysis - Tilak V. Bommaraju and Paul J. Orosz
        • Corrosion inhibition - Norman Hackerman
        • Dielectrics - William D. Brown, Dennis Hess, Vimal Desai, and M. Jamal Deen
        • Electric fish, electric organ discharges, and electroreception - Theodore H. Bullock
        • Electrochemical engineering - Richard C. Alkire and Thomas W. Chapman
        • Electrochemical machining - Joseph McGeough
        Electrolytic Capacitors - Electrolytic capacitors are capacitors in which one or both of the "plates" is a non-metallic conductive substance, an electrolyte.

        Electrolytic Capacitors

        Extractive metallurgy

        "Metal sulfide flotation concentrates can be treated in a number of ways. These include using pyrometallurgy, or smelting at high temperature, in which process the sulfur in the metal sulfide is oxidized with air or oxygen to sulfur dioxide, and molten metal is produced."

        Electrochemistry is the branch of physical chemistry that studies the relationship between electricity, as a measurable and quantitative phenomenon, and identifiable chemical change, with either electricity considered an outcome of a particular chemical change or vice ver

        Materials-Science of which Chemical/Electrochemical Engineering is a part; is behind all the development of electronic components and manufacturing. The Backbone is Applied Science. A Super Capacitor or a Special RF Semiconductor can only be developed using the research and efforts of these scientists.

        The Sciences or their study has been much nurtured and supported by some countries like the USA. This is the foundation on which many other Technologies like Electronics and Computing thrive. In many other countries this is many times not even perceived as its is not 'glamorous' and requires much efforts and dedication.

        "If the Foundation of Applied Sciences is sound, the Building of Technology is Sturdy"

        As said by - Elektrick Power Jedi - Charge Minds with Electricity - delabs Notes

        Friday, July 13, 2018

        Production Notes - Electromechanical - 01

        Production, especially prototype testing and Pilot Production exposes lot of engineering and serviceability issues. When you mass produce, it is more streamlined, yet the scope for improvement never ends. The process should always be open to feedback and improvements. - delabs

        Practical Electronics at Wikibooks - Nice page to learn basics before you study my points down below.

        Practical Electronics at Wikibooks
        Other essentials include a small pair of needle-nose pliers, side-cutting pliers, stainless steel or nickel-plated tweezers, wire strippers, a hobby knife with replaceable blades (e.g., X-Acto), and an analogue or digital multimeter with test leads.
        delabs Experience - Points to Note
        • The tracks or components on a PCB should not be near the mounting holes, the tracks may form electrical connections with the cabinet earth if they touch the pillar, washer or nut-bolt.
        • When you tighten the screws-nuts-bolt, limit torque by feeling or with torque limit screwdrivers, or thread will slip or PCB-Cabinet break, or CRT-Glass-Plastic will crack-shatter.
        • After assembly and testing is over on a board, do not drill-file it, it should have been done before. Else components crack or tracks break or small metal pieces will form shorts.
        • The Mechanical and electro-mechanical must be streamlined before production, for example when fitting the board the screwdriver may slip and break a zener. The product should be engineered in such a way that it fits easily and the testing and quality checks need not be repeated.
        • Some mechanical failures may not be visible but may show up as a field failure after even 3 months. this will make you lose further orders and ruin the reputation. Hence engineering is vital.
        • Alumina-Aluminum oxide powder mixed in epoxy resin (araldite) can make thermally conductive insulating filler, heatsinks. The Alumina must be free of moisture and very dry.
        • When you drive nails into walls ensure that that part of the wall is free of mains, telephone or any wiring.
        • Some pcbs can have hairline cuts or hairline shorts which will make troubleshooting difficult.
        • Never put or remove ICs, cards or plug-in modules when the power to that system is on, power off system wait for some time for caps to discharge, then insert ICs or cards, applies to PCs too, USB is a exceptions as they are hotplug, anyway even in this, take a bit of care.
        • Use RTV (room temperature vulcanizing) silicone rubber compound or Varnish on PCB-devices to avoid corrosion-dust. more so in industrial environment, ships and chemical industries.
        • Whenever you use nuts and bolts to fasten a PCB or parts to a cabinet use a spring washer, double nut or adhesive to prevent slip. When a loose nut falls on the pcb or transformer sparks will fly.
        • Do not mix mechanical and electrical connections, these leads to failures and frequent need of repairs and service.
        Tutorials on Basics and Instrumentation - Theory must be studied once and referred to, again and again as you do practicals. One is by building DIY projects and then modifying them. Also Repair of equipment, troubleshooting, testing and calibrating.

        Monday, June 25, 2018

        Facts of EMI and RFI from the Inside

        Electromagnetic interference (or EMI, also called radio-frequency interference or RFI when in radio frequency) is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source.

        Electromagnetic interference Wiki

        Vertical polarized VHF- UHF biconical antenna

        Vertical polarized VHF- UHF biconical antenna
        170 – 1100 MHz with omni directional H-plane pattern

        Who would know better about Radio Frequency Interference and ElectroMagnetic Interference more than the Hams or Amateur Radio Community.

        If they have to communicate effectively using limited resources, they have to deal with EMI/RFI effectively, While they build their equipment or combat Noise from other Machines and Installations nearby.

        This problem needs more practical involvement and experimentation to learn, compared to learning something like Digital Electronics.

        Equipment and Electricals like SMPS, AC/DC Drives, Motors, Solenoids and CFL Lamps are to be built/reinforced for low EMI/RFI emission/radiation.

        Radio Frequency Interference (RFI)

        Sensitive Medical Equipment like ECG or even a Aircraft can be seriously affected by Noise.

        Friday, June 15, 2018

        Design Notes - Analog and Opamps - 01

        Analog is the first thing in electronics. Valve Radios had Amplifiers and RF sections that were analog. Even the first computing methods are analog. Analog is close to Real Life parameter behavior. 

        LM335 and LM336 -

        LM335 is a temp sensor, LM335 . use it for temp for CJC. Temperature Sensors - RTDs and Thermocouples in  Temperature Measurement.

        LM336-2.5 is an voltage Reference. precision 2.5V shunt regulator diodes, Applied as a precision 2.5V low voltage reference for digital voltmeters, power supplies or in opamp signal conditioning.

        Current Loop -

        4-20 ma will drive DC drives, motors and steam valves. It is a current loop, for long distance transmission, current loop is not prone to noise and hum, EMI RFI. As it is a small power transmission no loss of data, also many equipments can be in one data loop. A single transmitter with 4-20mA out can drive a strip-chart recorder, motor, controller and SCADA input. all in a series loop. Current loop is like 4-20 mA

        Opamp Notes and Types
        • TL062, LF353, TL072, fet input. 1 tera ohm input imp.
        • OP07 higher price, 1 giga ohm. 75uV offset.
        • LF353 pin to pin replacement of TL062-72 and 82.
        • LM358 works on single supply too, low price, inp imp 1 meg.
        • LM324 Quad, works of batteries well.
        • All work best with dual +/- 5 V or more. LM7805 -LM 7905.
        Analog Electronics: Basic Circuits of Operational Amplifiers

        Examine the operation of the following circuits of operational amplifiers: inverting amplifier, summing amplifier, difference amplifier, differentiator, and integrator.

        Remembering Bob Pease

        Remembering Bob Pease

        Points to Note -
        • Analog ground (opamps), digital ground (CMOS) and power ground (relays and LED) should be separate, (linked at root)
        • Glass epoxy PCB have high insulation resistance, above 10 tera ohms, and are not hygroscopic which means they do not drink water vapor, this makes them very suitable for precision instrumentation and sensitive circuits.
        • When you measure DC levels in 16bit accuracy or more you need resistors which have temp. coeff. of 10ppm, or you may have to put the entire circuit in a stable 45 deg oven. Thermoelectric effects, EMI, RFI, pA Leakage currents, ground loops, contact resistance all can make the readings drift and unusable.
        • High impedance points of circuit like 500 kilo ohm and above can pick up AC noise and DC leakage currents. this will affect the performance of circuit, so for DC you have to put a guard ring of the signal ground around that point in PCB. For RF you have to shield with things related to iron and mu metal, for low signals even a copper shield will do.
        • Percentage and ppm: when percentage becomes like 0.001% it is difficult to manage, so we use ppm-parts per million.5% means 5 parts in 100 parts. 23 ppm means 23 parts per million parts. 0.001% - shift the dp-decimal point four places to right it is 10ppm. 0.01% is 100ppm which is the variation of value of mfr resistors on temperature change.
        delabs design Notes from the 90s  till 2004
        Learn this at my Industrial Process Control Circuits

        Thursday, June 14, 2018

        Lightning Bolt damages Components

        A ThunderBolt Zap can damage electronic parts. The Earth Leakage Circuit Breaker ELCB or Overload Breaker may Trip.

        Surge Protection and Lightning Arrestors

        Mains Strip Board should have protection, The EMI RFI filter, Varistors can help. Earthing and Lightning Arrestors should be good in the building.

        The Blue ones are MOV Metal Oxide Varistors, sometimes they fail as a short circuit, so better to use a fast blow fuse. Then you see Gas Tube Arrestors that are even used in a Landline Terminal Box.

        Surge Arrestors

        A Surge Arrester is a device to protect electrical equipment from over-voltage transients caused by external (lightning) or internal (switching) events. Also called a surge protection device (SPD) or transient voltage surge suppressor (TVSS),

        Friday, May 11, 2018

        Instrumentation and Automation - 01

        Here are some Test and measurement notes. These ideas come from practical experience. But the jots are not in any order but are quite important.

        DuMont Lab Oscilloscope

        Scope Notes
        • If the waveform on the scope droops then you may need to use a 10X attenuating probe or mode. this attenuator is at the tip of the probe hence better measurement possible, also very high frequency signals may be best transmitted over a 50 ohm impedance matched line to the Oscilloscope. 
        • Karl Ferdinand Braun - In 1897 he built the first cathode-ray tube...oscilloscope. CRT technology is to this day used by most television sets and computer monitors. The CRT is still called the "Braun tube".
        • Do not use an oscilloscope to measure 230V directly, use a transformer, differential probe or attenuator.
        • An oscilloscope 1M probe or a DMM 10M impedance can load circuits with nano-pico amps of bias.

        DMM Notes
        • Test a NPN transistor, DMM in 200K range. emitter negative probe, collector positive probe, it should show open. while still holding that way press wet finger on base and collector, it may show some reading, then it is ok. for PNP swap probes polarity and do the same thing. the wet finger when pressed applies a base current in uA.
        • The most common reason of DMM failure is when a person tries to measure 230V AC with a DMM in current or ohms mode, with the probes in the wrong sockets. Use external attenuators and shunts.
        • A DMM in diode mode or resistance mode can be used to test IR diodes, take it under 100W lamp and measure, cover the IR diode and measure you will see a response in proper polarity.
        • If you put the DMM in 2V mode and measure the voltage across a ordinary LED near a 40W lamp you will see around 200mV. Turn off 40W lamp the mV will fall near 0. Even metal-can transistors with their top ground away will become photo sensors.
        • When you measure low voltages or high resistance like 1M with a DMM your body must not be in contact with the probe tips. Body resistance is low in comparison so error in reading or loading of mV from sensor, in sensitive and high impedance ranges.
        • Red socket and probe for positive and black socket and probe for negative
        • Is it oscillating ?.... We cannot say, it could also be DC, you need to see if a Clock is present. use a signal tracer or a DMM freq mode, or AC measurement.
        • Polarity and Zero Cross indicators tell you to swap the leads. Use a comparator or opamp to build it.

        Monday, May 07, 2018

        Multi Zone Process Monitor

        Here is an ancestor of the product in the earlier post. It is a Process Scanner and Indicator. There was no control, but there were individual alarms for each channel.

        Multi Zone Process Monitor

        This is a original design of mine, obsolete now due to size and technology. The inspiration of the product concept was from a Omega Catalog Item. Even today i use the Omega catalog for inspiration, but i do not design complete products, only circuit sections.

        Read more about Control Instruments at my pages here

        Thursday, May 03, 2018

        EE and Computer Online Learning - MIT

        Free Online Course Materials for EE and Computers. Here are resources useful for the EE Students and Teachers. These are at MIT and they are available for all. It is a OpenCourseWare (free).

        Electrical Engineering and Computer Science at MIT

        "MIT has awarded electrical engineering degrees for nearly 130 years, and our educational programs have been at the cutting edge since their inception. We provide an in-depth education in engineering principles built on mathematics, computation, and the physical and life sciences, and encourage our students to apply what they learn through projects, internships, and research. "

        EE and Computer Online Learning - MIT

        delabs Notes

        Students can enhance their learning even at home after the classes using these materials. This will help you grasp what happens in the college the next day.

        It is also important to keep yourself physically fit. Some jogging, swimming, cycling and light workout will even strengthen the nervous system.

        I would not like to write this here, but i have to. My own experience. Do not build muscles for looks or abnormal growths. Some use hormones, over exercise and even some medicines like steroids for artificial growth. At a later age it causes lot of problems due to accelerated aging. Even athletes should refrain from these for the long term interest of their health.

        Wednesday, April 18, 2018

        Ergonomics and Safety of the Workplace

        Ergonomics and Manpower the Engine of Growth -  A Worker in One Firm is a Customer for another Firm. Healthy and Safe Workers implies a strengthening Consumer base.Just imagine what wonders it can do for the economy, when you broaden your view, think togetherness, as a Whole; not in isolated competitive groups, not in parts.

        Ergonomics reduces Worker Stress. Helps in keeping good Mental and Physical Health. Safety is very important. His Limbs, Eyes and Ears are assets that a firm hires.

        Ergonomics and Safety of the Workplace

        A good Manager knows that Manpower is the Foremost Asset of any Company.

        Thursday, April 05, 2018

        Two Setpoint Temperature Controller

        A Two Point Process Controller or Temperature Controller would look like this. When a High-Low Alarm Protection for uC based Controller was needed the same was modified and used.

        Two Setpoint Temperature Controller

        Sometimes uC based instruments just forget and that can be costly, the watchdog timer has solved this problem. In Industrial Process Control we cannot take any chances, so a two tier or even three tier protection is required, especially so if the Job or Raw material being processed is expensive.

        Temperature Measurement and Control

        So Real Time Analog Trip + uC Controller is safe. Then you can still have Electro Mechanical Devices for Extra protection against Fire or Meltdown.

        Sunday, April 01, 2018

        Safe and Sound - Product Safety

        Caution is better than Risk, Prevention is better than cure. using the the right tools for a job alone is not sufficient; You have to get trained and informed about its proper use and safety precautions.

        When we Design a Product or Develop further a design; we have to integrate Product Safety into the usage method and improve usability and safety. Product also has to be Engineered in such a way that manufacturing it does not pose hazard to the worker.

        Safe and Sound - Product Safety

        Product Safety
        • Product should not give even the lightest shock, Even metal parts on user side to be laminated.
        • High energy circuits never enters analog and digital circuit areas without Opto or other Isolation.
        • Gadgets, Furniture, Tools and Storage Units should not cause injury. Rounded Edges, Non Toxic.
        • LED and Lasers can damage Vision, welding too. Use Protective Filter Glasses. After a comment by John Bump

        Friday, March 23, 2018

        Wiley InterScience - Technical Content

        Introduced in 1997 and launched commercially in January 1999, Wiley InterScience is a leading international resource for quality content promoting discovery across the spectrum of scientific, technical, medical and professional endeavors.

        Wiley InterScience - Technical Content

        Enhanced Tools to Discover Relevant Content: Comprehensive search engine optimization ensures easy discoverability of content, delivering relevant and immediate results to users.

        Wiley InterScience - Technical Content

        Industrial Engineering

        Subjects like robotics, Engineering Management, Industrial Reference Books and Manufacturing Engineering. Includes Plastics, Metals and Mechanical Engineering aspects.

        Electrical & Electronics Engineering

        The topics here are Electronics and Communications, Reliability, Testing Technology, Industrial Electronics, Process Control Methods, Lighting and Power Supplies too,

        CrossRef -

        Connect users to primary research content, by enabling publishers to work collectively.
        CrossRef is an independent membership association, founded and directed by publishers. CrossRef's mandate is to connect users to primary research content, by enabling publishers to work collectively.

        Wednesday, March 21, 2018

        80C31 and 8052 Microcontroller

        8048 and MCS-48 made designing with Microprocessors easy with built in I/O ports, RAM and Timer. The I/O ports for the 8085 was an external 8255. 8749 enabled users to burn and test firmware on an integrated UV Eprom.

        80C51-52 which came out as the fully evolved uC had built in Serial Ports UART and more Math, better Timer-Counter and Interrupt Handling. The 'C' is for CMOS that made handheld instruments possible due to low battery usage and lesser support chips.

        Here is a kit from Bipom that may help you learn more about the basics of embedded systems with a SBC,

         MicroTRAK Bipom 51-E Complete

        MicroTRAK Bipom 51-E Complete

        MicroTRAK/51-E Complete includes MicroTRAK Carrier Board, MINI-MAX/51-E Microcontroller Board with Ethernet, TB-1 Training Board, MMC-RTC-1 board with Real-Time Clock and 128MB Multimedia Card (MMC), 8051 I/O Module

        The Assembly Code MCS-51 set is used to program the chip. There is a 8052 Basic that can understand the Basic Language, useful for people who are not comfortable with mnemonics.

        Now we have 8051 chips with EE Flash and some have a watchdog and I2C too.

        80C51, SBC, Firmware and Circuits

        80C51 Single Board Computer SBC and Firmware Code. Interface 8051 or 8052 to PC on a RS-232 or serial port. Microcontroller Board and learn about MCS-51.

        delabs circuits - micro1

        Saturday, March 17, 2018

        LED Lighting and LED Lamp Drivers

        LED Lighting is gradually replacing CFL Lamps because they are more frugal in drawing energy and last many years. These have been around for some years and the technology is progressing. Now LEDs which show the illuminated objects in their true colors (like sunlight) are also coming. Due to the green initiatives of many countries, people have become aware and also implementing these solutions. These become a necessity when you start using Solar Panels for Home Power.

        LED Lighting at delabs Tech

        LED Lighting and LED Lamp Drivers

        The CFL lamps have reduced the use of the Filament Bulb due to lower power consumption. Now LED lamps may have to replace CFL but it is progressing. Few years ago only Conference Rooms, Media Events or Product Exhibits could afford the LED lighting, it was a Novelty. Now LEDs are affordable and Reliable Driver Solutions are also available.

        The problem like in most Tech Learning Curves is now the SMPS drivers for these LED Arrays. The LEDs are reliable, but drive systems are still having problems. Cost effective drive systems from make affordable lighting possible. But due to Quality and Reliability issues, system integrators face implementation problems.

        When Mitutoyo the maker of the Best Metric Tools started decades ago, it faced a tough market. In those days, Japanese Goods were known as cheap and low quality in Europe and America.

        Companies like Mitutoyo, Sony, Misubishi, Hitachi and many more changed the scenario completely. Now Japan is a Symbol of High Quality. Every new firm has to go thru those Stages.

        A genuine long term commitment to R&D and Quality will build the reputation of Brands, Firms and entire Regions. Anyway, here are some nice resources to help build Drivers and Systems for LED Lighting.

        Learn how to make drivers at delabs Power Electronics Section

        These Semiconductors and Applications are Excellent, the driver systems have to be engineered and perfected by manufacturing and development. A casual or quick results method will backfire. Hence system integrators start by working closely with the vendor (Vendor Development) of Drive Systems. Finally deliver only systems that are Robust and Burnt in. The other option, work with know friendly customers as a Beta Testing and learning phase, till systems reliable for global deliveries.

        Sunday, February 25, 2018

        Control system design Notes

        Proportional Controllers not only save energy, they can give a controlled finish or treatment to a job. An on-off controller or thermostat limit protection has to be used in series, this is to to stop a Runaway Process.

        Control system design Notes

        There was a real life instance when a Temperature cycling oven maker (environment chamber), faced large liabilities as an 8086 based profile controller and chart recorder just locked up and all the electronic equipment were roasted. Here even a bimetallic thermostat would have saved the day. Nowadays we have a watchdog timer to prevent such uP mishaps, but still use an analog controller in series as an over temperature trip.

        Other Reading

        The basics of control system design: Part 1 - Moving beyond PID

        "This series of six articles will explore the use of six variations of P, I, and D gains: Proportional Control, Proportional-Integral Control, Psueodo-derivative feedback with feed-forwared (PDFF), PID control, PID+ control, and Proportional Derivative Control."

        Saturday, February 24, 2018

        Blind Dial Analog Temperature Controller

        This is a Low cost controller, Analog Dial Temperature Controller. It is also called Blind Controller. This essentially means Open Loop, just control the fuel or energy input to the system to regulate heat. This is not a Blind Controller that way, it only cannot display the temperature value, that could be another reason it is called blind.

        Blind Dial Proportional Temperature Controller

        Blind Temperature Controller

        Dial cyclic timers were used to control heat, these were purely mechanical clockwork devices. They could regulate well, when the material flow (liquid) is constant and mains power is regulated. But when the job to be heated, varies in quantity, control temperature is close to ambient or when a precise control is required; closed loop controllers are used. Even a thermostat is like closed loop, as the bimetallic sensor is temperature dependent. But not good enough.

        This controller is closed loop, precision controller, only the digital display of temperature is absent. Fine one deg variations may not be easy in this.

        Monday, February 12, 2018

        Electronics Tutorial for Robotics

        This tutorial will take you through the basic elements of circuit design, with the goal of preparing you to design and build robotic sensors and control systems. The experience of designing and building is at least as important as gaining conceptual understanding.

        Electronics Tutorial for Robotics

        An oscilloscope is an invaluable tool for learning circuit design -- it provides a way of seeing what is actually happening to your signals and waveforms. Unfortuantely, oscilloscopes are somewhat expensive. If you don't have access to a 'scope, it is possible to use the data-logging features of the Lego RCX in its place

        Electronics Tutorial for Robotics

        Using Chips

        Op-Amps are the first components we've used that are integrated circuits, which are also called IC's or chips. IC's are easy to use, but we need to know a few things about them.

        D. Sculley, Ph.D. an Alum of Tufts University wrote this tutorial in the summer of 2004, teaches  basics of electronics, created for Tufts Robotics.

        Monday, January 29, 2018

        Thermocouple and Current Input Module

        This input module converts J, K Thermocouple and 4-20 mA Inputs to 0-2V Full Scale. These can be used for any voltage/current inputs too. The RTD module can be modified more easily for Voltage inputs. The control output can be On-Off or 4-20 mA/Proportional with another card. The 4-20mA I/O STC1000I is not complete in documentation.

        This is a Input Signal Conditioning Card for the Temperature controller. The voltage levels from sensors are either too low or need to be translated in level and span. Then for greater accuracy some linearization methods have to be used for a more precise reading. This also increases the cost. The circuits here do no cover the linearization see others in this and my related pages.

        Input Module - J and K Thermocouple with 4-20 mA

        Input Module - J and K Thermocouple with 4-20 mA

        The step or segment linearization can be done by transistor, diode or CMOS switches to accomplish varying attenuation/gain for stages of the curve or voltage levels. In Microcontroller systems it can be done by lookup tables or math.

        In some older digital systems without a MCU, the A to D drives the address of an Eprom Array to get a Digital Data for Display, as a linearized Reading. This Corrected Data was in turn made into analog using a D/A and then on to a Chart Recorder. This was a Logic only System of the early days. Microprocessor systems was expensive, power consuming and use to frighten people by getting lost in loops or a short nap.(they have fixed that, make sure you code properly).

        Wednesday, January 24, 2018

        PCB SSR Module - IO Module

        This is a PCB Mount SSR for Control of a Small AC load like a Lamp or a Contacter. It has Optical Isolation and has a Thyristor for output. This was in the I/O Module Standard.

        PCB SSR Module - Enclosure

        The MOC3041 A zero crossover optical triac driver is used here. The footprint is very small, many can be stacked in one small PCB.

        Read More - PCB AC Load SSR with DC control.

        You can see in the PCBs below  the distance between the input and output tracks is more than 5mm. The opto is itself a few kilovolts of isolation and we should take care of the creepage distance on the PCB and surface.

        This thing is Hermetically Sealed using a Alumina Powder filled Epoxy. This combination gives good thermal conductivity and Excellent Insulation.