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Power Output Measurement with a generator but no scope - Printable Version

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Power Output Measurement with a generator but no scope - K O'Connor - 09-19-2018

Hi Guys

As you acquire test equipment, you might buy things in the order you can afford them and so might have a sine wave generator before you have an oscilloscope. this would be an odd order for most people intent on having a well-equipped bench. Or maybe your scope has died and you still have to do some testing?

To test output power of an amp with a generator but no scope requires at least an AC voltmeter and a bench load. The procedure is the same as for no-scope and no-generator EXCEPT you have the generator - hehe.

Connect the generator to the amp input. Connect the bench load to the amp output. Connect the AC voltmeter across the load. Set gain or volume to zero.

Turn on the generator and the amp.

Dial volume up until the meter gives a steady reading. Note the value and dial volume back to zero.

The voltages for clipped power, so we can calculate power then divide by two for sine wave power.


RE: Power Output Measurement with a generator but no scope - Steeveejay - 11-04-2018

Hi Kev , I have lately been using a mobile app on a smartphone called audio tool , to generate sine wave into an amp , but mainly for signal tracing . Could this be used to test output ?


RE: Power Output Measurement with a generator but no scope - K O'Connor - 11-04-2018

Hi Steeveejay

It would work provided there is enough output from the phone and/or enough gain in the amp. Testing a complete guitar amp should be okay but testing just a power amp might not .

Have fun