AC Volt and Amp Meter with a 0-5VDC linear output

[ElmVideo]

Hi,
I want to build a 120VAC Voltmeter AND a 0 - 30A AC Ampmeter (safely isolated and seperatley, not a 'power meter') that will give a 0 - 5 VDC linear output. For example, a 120VAC RMS input voltage would give me a 1.2VDC (very low ripple) output. A 3.2A AC current would give me a .32 VDC output (very low ripple). Also I want to use my existing power supply that is a single supply, I can regulate it to +15V if need be. I have tried many experiments but all produce poor results, and just interfacing the high voltage line is a problem. Any help would be appreciated, Thanks, Eric

 

[ljcox]

You need to use op amnps with a gain of 10. There have been plenty of posts recently about op amps.

As for isolating the current, you could use a current transformer. There is a recent post on this also.

Len