DMM range and AC-DC mode Logic
This is the third circuit that you will need to build a Simple Benchtop DMM with no Microcontroller. Here the U1D and U1B 4093 acts like a de-bouncing circuit for the push keys. The...
Category: Instrumentation
Power supply with battery backup – DMM
This is a simple charger circuit which will work for a light load like a DMM, the Battery can be a sealed maintenance free battery of 9V-2AH or better. The circuit will work best...
Build a DMM – LM3914 Analog display
This a part of a complete Benchtop DMM that you can build to learn the internals of a Digital MultiMeter. This is oriented towards learning the measurement aspects and the protection of input circuits....
AC conversion and Continuity – DMM
U1A LF353 opamp turns on a buzzer when the voltage at Test + falls very low indicating a short between Test + and Test – or a resistor less than 5 ohms. The R9-R14...
Interface ICL7135 Voltmeter to 89C52
This circuit is a Parallel interface between 89C52 of Atmel with 7135 of Intersil. With This circuit you can read analog data of both polarities. You can change the range scale with extra circuits,...
Current Source for Resistance Measurement
Here is a current source you can build for resistance measurement. When the current is held constant, you know as per Ohm’s Law the Voltage across Resistor is proportional to Resistance value. The supply...
Ohmmeter – Simple Resistance Measurement
Measurement of resistor values in circuit configurations are required to be made often, as these might have changed in value due to various tolerance ranges, and hence could be the cause of faults. Likewise...
Ammeter and Precision Rectifier
Studying current measurement is a prerequisite for many of the measuring techniques. The current parameter mainly specifies the power consumption in a circuit, given the value of resistance. It is found convenient to measure...
