The circuit diagram of simple capacitance meter has been published here. The core part of this circuit is the frequency to voltage converter IC LM 2917 developed by National Semiconductors. This IC LM 2917 is a monolithic IC having a very high gain. This IC has got its primary application in tachometers. It can also be used for other applications as well.
This is a capacitor measurement circuit that displays capacitance by using a meter M1. The capacitor Cx whose capacitance is to be measured is connected between the pin2 of the IC and ground. The capacitance Cx will be proportional to the output voltage of the IC. At the output pin (pin4), a resistor R2 (10K) is connected as load. The voltage across this is displayed through a voltmeter (M1) which is connected across R2.
- Use a Vero board to assemble this particular circuit.
- Use a suitable holder to mount the IC LM 2917.
- Capacitance values from 0.01uF to 0.1uF can be measured using this circuit.
- Potentiometer R1 (200K) can be used for calibrating this circuit.
- Use a 10V FSD voltmeter in place of M1.