delabs Circuits

Wednesday, December 10, 2014

Digital Insulation Tester

This is a photograph of a 20 Tera Ohm Insulation Tester I made around 20 Years Back. It had even Polarization Index for Transformer Insulation.

Digital Insulation Tester

The Product above is made with two circuits below.
A regulated, low ripple, high voltage of very low current capability is applied by instrument on a DUT (device under test). The leakage current in nA or pA (picoamps, nanoamps) is measured and readout, The Innovation i did was to measure the current in Vref and not Vin of ICL7107, this made the 1/x computation.

Insulation Tester or Tera Ohm Meter with Polarization Index

Also using the ICL7650 Chopper Stabilized amplifier must be done as shown in data sheets with grounded guard rings. pA will leak on the PCB itself if layout is not done keeping this in mind.

Sunday, December 07, 2014

DMM or Digital Multi Meter

Digital Multi Meter - New Year Resolutions
  1. I will not drop the DMM from a height of 4 feet.
  2. I will not Test Live Powered equipment in the Ohms Mode.
  3. I shall not Measure Mains Voltage in The Current Mode.
  4. I shall get it calibrated once a year or at least once a decade.
  5. I shall not use it in High Energy Measurements.
  6. I will try my best not to give it to my best friend.
  7. I can remember Red is Positive and Black is negative.
  8. I will wear shoes and stand on a block of wood while i test.
  9. I shall not operate the rotary range switch at high speeds.
  10. I shall replace the probes-cables-connectors on wear-tear.
  11. I shall not accidentally keep the hot-iron near the DMM or leads.
  12. I shall not keep DMM on tall table and pull it with the leads.
DMM - How it Looks ... shown is from Fluke Electronics

DMM or Digital Multi Meter

How To Learn Electronics :

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. Then you know how components behave and real life limitations. Now design and engineer a product and test it at customer site. do a pilot production and test with more clients. Now you will learn to think based on practical applications.

"with hard work and innovation you can do it ! "  Solderman Talks 1702 AD

- Solderman Talks 1702 AD

Tutorials on Basics and Instrumentation Electronics


More About DMM

Thursday, December 04, 2014

Transformers Series and Parallel Connections.

Series and Parallel Transformers

Series and Parallel Connections in transformers. Observe the Dot-Polarity. When windings are in parallel the current capacity doubles. When windings are in series the voltage doubles. Wrong dot polarity in series connection just cancels the voltage and a small residual imbalance voltage remains. If wrong polarity connection is done in parallel, then a short circuit or overload may occur.

Basic Electrical Circuits

Series and Parallel Transformers
Center Tap Transformer

This is when you need to build a symmetrical dual supply like +12V and -12V supply for an opamp design.
This is also good for a two diode full wave rectifier. But when you make a dual supply use a bridge and the center tap is ground. If you use just two diodes then one winding may be loaded more than other. That may not be good for long term transformer life. The core may get magnetized.

Center Tap Transformer

Contents

Basic Electronics
Basics of Electronics
Product Production
Work Discipline
Testing Points
Learning Electronics
Electronics Theory

Production Notes
Prototype Fabrication
Electrical Circuits
Electromechanical


Library
Scots Guide Electronics
Engineering - Wikibooks
Design Lab - Jim Svoboda
DC Circuits UOG
Socratic Electronics
Blobz Guide Electric Circuits


Product Design
Product Development
Constant Current Source
Good Voltage Regulators
Insulation Resistance
Digital Insulation Tester
DN Schematic PCB 04
DN Product Design 07


Hobby Circuits
VU Meter Circuits
LED brightness control
555 Incredible Chip
Process Control
liquid level measurement
Thermocouples and RTD
Design ADC Interface uC
Thermocouple Amplifier
IA Instrumentation 02
Temperature on DMM
Optical Proximity Switch
Analog Mux - Data Acquisition


Test Measurement
Instrumentation Automation
NI Test and Measurement
DMM Digital Multi Meter
Oscilloscope in T&M
IA Automation 01
Build Instruments
Tektronix T&M Equipment
Educators Corner – Agilent


Power Electronics
UPS Background
Transformer Connections
DN Power Electronics 03
DN Power Electronics 02
Half Bridge Convertor SG3525


Embedded
Interfacing Microcontrollers
Embedded Process Control
80C31 8052 Microcontroller
Microprocessors and uC
Embedded Systems Design

Components
Good Voltage Regulators
Relays and Contactors
Potentiometers Trimpots
Prototype Boards Types
Types of Capacitors
Types of Switches
Resistors How they Work
Coils Transformers SMPS
Mains Transformers Types
DN Components Selection 05

Tutor Gadgets
Count-Up Timer
Digital Logic Gates
Electronics Tutors

History
Teaching Instruments
Charles Proteus Steinmetz
Muntzing a Circuit Design
Teralab Electronics projects
Historical Instruments


Tables, Charts, Videos
Binary and Hex
Resistor Color Code
Ohms Law
Giga, Tera, Pico, Nano
High Resistance Materials

Analog
School - Analog Design
DN Analog Basics 06
DN Op-Amps 01
TI Semiconductors