Digital Ac voltmeter Using 7107

[Suresh mano]

Hi ,

 please Help me to assemble a digital ac voltmeter using ic7107 .   Anybody  give the circuits.

 

[audioguru2]

The ICL7107 is very old and has problems with accuracy when it warms up. The ICL7107S is an improved one.

Its datasheet has a circuit that is recommended by the manufacturer.

 

[sureshmano]

Please Send me that circuit

 

[admin2]

You will need to convert your AC voltage to RMS voltage then feed it to ICL7107. Datasheet has such a circuit on page 14. I attaching it here for your reference. The connection to the display is as the second attachment.

 

[suresh mano yahoo]

Can i give Direct 300Vac at ca3140 in Series with 100Kohms..

I need to Measure 300VAc In this circuit please. Help me to design this circuit..

 

[audioguru2]

300VAC has a peak of 424V that will arc across an ordinary 100k resistor and destroy any opamp.

Use a high voltage 100k resistor, a voltage divider and a voltage clamp that limits the opamp input voltage.