Voltage Attenuator Amp – DMM Project
LF356 opamp FET input is in a inverting amplifier configuration here. R4 + R5 make up Ri each 1/4 W MFR withstands 250V so both will take upto 500V. Use more in series for...
Category: Test-Measurement
Diode Thermometer
Measurement Of Temperature – When power transistors are used, they may tend to over heat. Likewise resistors may also overheat in the event of faults or short-circuits. The knowledge of their temperatures may be...
Millivolt Source with Digital Potentiometer
Variable Parameters like voltage, current can be obtained by using a Digital Potentiometer. Microcontrollers or Counters operate FET CMOS Analog Switches. The switches configure resistor networks to adjust circuit performance. It could be a...
Millivolt Source – Field Calibration Current Loop
This is easy to rig millivolt source for field calibration or troubleshooting of 4-20 mA current loops. Here a Darlington pair is used for current amplification which reduces the Ib error as gain is...
2.5 GHz Frequency counter
“Imagine you have a radio receiver and you wish to display the receiving frequency. As you know the oscillator in a radio receiver works 455 kHz or 10.7 MHz above the receiving frequency. The...
Diode Reverse Bias Leakage Tester
This is a Test arrangement for Leakage Testing of Diodes on Reverse Bias. The leakage current indicates the ability of the diode to withstand higher voltages. An AutoTransformer or Variac can be used to...
Mains Voltage monitor using LM3914
This Circuit helps in the monitoring of mains supply voltage. It does not use a isolation step down transformer. This has to be constructed only by skilled people with knowledge of safety requirements. C1...
3-1/2 Digit ICL7107 DPM Digital Panel Meter
This is a Digital Panel Meter based on ICL7107. This was the workhorse Digital Readout chip before Low power uC designs were developed. Even now it is the easiest way an analog parameter can...
Digital to Analog with R2R Ladder Network
This is a R-2R Digital to Analog Converter, It converts a byte (8 bit) to a analog value. It has 256 levels including zero. This was the first Digital Pot i Built decades back...
High Resistance Meter
I don’t remember if this circuit worked properly. But a few were made and i might not have shown the modifications that were done to make it work. This was meant to be a...
Amp Hour Meter using LM331 and 74C926
LM331 is a Voltage-to-Frequency Converters and 74C926 is a 4 Digit Counter. The first part of the circuit converts the amplified DC analog value from a shunt to pulses. The Second counts the pulses...
Ramp Generator – Triangle Wave Generator
Two questions on Ramp Generators – I need a circuit design for a ramp generator. The ramp generator circuit that I’m looking for is a 1khz ramp generator capable of + to -50 v...
