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 and Firewire ports are 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.
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),

Line-Filter - A special class of capacitor is used in power-line (mains) filters.  Line filtering is a very tough application for a capacitor.

Achieving EMC for Dc-Dc Convertors - DC-DC converters, whether they be an off the shelf brick design or a discrete equivalent, are a source of EMI (Electromagnetic Interference). EMI is unwanted electromagnetic energy that propagates by radiation and conduction over system signal and power lines.

SMPS switch mode power supply design, PSpice simulation - These definitions should be considered relevant to a SMPS, and may not apply identically to other technical areas.

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. or build this solorb.com-elect-logprobe. When you do not have a scope you can build one for the PC.
  • 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 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.
First Aid and Flame Resistant Uniforms

Tools and Apparel to make workplace safe. First Aid and Safety, Fire Protection and Flame Resistant Clothing. Cleanrooms  are very important for Microelectronics, MEMS and Precision Instrumentation.

In spite of "Prevention better than cure", a worker can get injured, more so on the field, where preventive measures may not be in place. A Portable First Aid Kit that should be in Service and Commissioning Departments. A stitch in time saves nine. in reference to: "Your employees may require first aid at remote worksites, too."

Worker Safety and Health Education

When we educate ourselves about a Hazard, that awareness is the first step of defense. Resources like this should have a Kids Section. Just like Nasa and Fcc have. We have to catch them young, Interactive tutors and Activities will prepare them for a Safe and Sensible future. Home, Garden, Transport and School are also like a Workpace.

Kids of recent generations are degrading intellectually, it is more so in the developed countries. Education has to be emphasized, Hobby DIY activities encouraged. Hardships simulated, so they become responsible Young Citizens.

Rockefeller Jr. (A Philanthropist) was brought up with such discipline, he was not allowed entertainment when he was young. His father the richest man in the US at that time.

Resource for Workers and Employers. CDC - Workplace Safety and Health

Intrinsic Safety and Zener Barriers

Designing and Building Intrinsically safe Industrial Systems is of paramount importance as Human Safety is involved. Even in Switching Loads some contactors, relays, circuit breakers and motors are hazards as some sparking becomes inevitable.

Intrinsic Safety - Omega.com

Solid State Relays are safer but on an overload even these can pose a fire hazard if a HRC fuse is not used. Sensor measurements must employ low voltages and currents. Even cabling management and hermetically sealed enclosures may be required when volatile fluids are close by.

delabs Notes - 2002 -2005

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.

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

Temperature is the most common process parameter, Pressure seems to be next. Flow, Level, RPM, Distance and many more follow.

Two Setpoint Temperature Controller

When a physical parameter let us say distance is measured, we first need a sensor that converts it into electrical values, digital or analog. The sensor used for length is a Linear encoder and it creates the electrical information for the DRO to Display.

Now many sensors like a strain gauge produce very low and weak signals and some are non-linear. So the signals undergo Amplifying, Temperature compensation and Linearizing together called Signal Conditioning. This stage outputs some standard values like 4-20mA, 0-10 V, 1-5V, or even directly digital or wireless in the new technologies. Even when a digital interfacing standard is used, amplification and some signal conditioning is required at sensor end. Compensation and Linearizing can be better done with a uC using Math or Look up Tables.

When you have many different parameters then it is better to use process controllers with a 4-20mA input standard. Then the inventory of controllers can be reused for any process.

It is always better to use sensor-end transmitters to get 4-20mA to your Controller, Recorder or SCADA System.Weak signals are corrupted by noise and dont travel long wire distance. Junction EMF at joints and terminal blocks add to errors. These are overcome by the 4-20mA signal that has the juice and punch to transmit the data over the shop floor to the control panel rooms.

Read more here Temperature Measurement and Control

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
Worker Safety
  • Helmet, Goggles and Face/Respiratory Mask when working with power tools/ abrasion and large objects.
  • Crepe Bandage, Neoprene Ankle/Knee/Thigh Support when pushing or pulling or Physical Exertion.
  • Waist/Back Support Belts and Straps to reinforce back/spine while doing Heavy Lifting or Movement.
  • Waistband Thick Belt or Traditional Sash helps Posture and prevents slipped disc or spinal injury.
  • When using a Knife, Sharp Tool, Pointed Tool or Drill; cut/bore away from your body or finger/leg not towards.
  • Use Long Riding Leather/Synthetic Boots when working in chemical plants and heavy industry.
  • Cross Ventilation and exhaust fans important if even little chemical fumes are generated in your work.
  • Soldering, plastic forming and even for some kinds of material processing. Good Ventilation or Masks needed.

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 and New technology Innovations. Other countries should follow this Golden Example set by Japan and its Products. 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.

Monday, February 26, 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."

Sunday, February 25, 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

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.

Blind Temperature Controller

PCB Boards for Blind Controller -
Discussions -

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.

Tuesday, January 30, 2018

Interface a PC to Measure or Control Temperature

Thermocouple, RTD, Temperature monitoring is central to the majority of data acquisition systems, be it to save energy costs, increase safety, reduce testing time…whatever your reasons, you will need a device to measure the temperature - a temperature sensor.

How to Use Your PC to Measure Temperature

Thermocouples, resistance temperature devices (RTDs), thermistors and infrared thermometers are all types of temperature sensor. Which you choose depends on factors like your expected maximum and minimum temperatures, the accuracy you need and your environmental conditions.

Interface a PC to Measure or Control Temperature

Windmill data acquisition software with Microlink hardware

752-RTD: RTD Resistance Temperature Measurement, Digital I/O, Counting, Analog Output
  • Measure temperature using RTDs or Pt100 sensors, and voltage signals
  • With extra hardware monitor thermocouples and strain gauge bridges
  • Includes the powerful yet easy-to-use Windmill software for Windows: no programming required
  • Connect up to 8 USB units to one PC
Here is a way you can learn, How To Interface PC to the Outside World.

Temperature Control with a PC

delabs Notes

This is a project that will help students learn both hardware and software aspects of a control system. Here you can test out an automation program on a PC with minimum external hardware.

When you implement in the field, the system has to be a dedicated real time uC based product on custom firmware. Systems with OS + Software combination are not known to be reliable in Process Control. But OS + Software is good for Supervisory Systems which get their data from Real Time Controllers.

So a front end controller must be Rugged, Non-PC based and Non-OS based embedded system. With a Robust and Compact (means fast) firmware.

The firmware should be Polling or Interrupt based but with both internal and external watchdog. Most important a Power supply Management that resets system properly over Brown-outs and Black-outs. Even today some Embedded Systems i have to turn off and on after power resumes.

Don't Forget, Multiple Watch Dogs and Multiple Power Management for graceful start of system !! Use one big SuperCap if you want. Else people will go back to Thermostats.

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.

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555 Incredible Chip
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liquid level measurement
Thermocouples and RTD
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Thermocouple Amplifier
IA Instrumentation 02
Temperature on DMM
Optical Proximity Switch
Analog Mux - Data Acquisition


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