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You built an amp from scratch but you don't know how to test for output power? You should have a rough estimate of what power you will get from the voltage rails.
Take a load resistor of 4 ohms, 2 ohms, whatever you want to test at, make sure the resistor can handle the wattage you think you have. Connect this to the output of the amp, hook an oscilloscope to the outputs so you can view the waveform. If possible find a way to measure the current coming out of the amp with a clamp on ammeter, current probe, the best way to do this is without inserting a meter in line with the load. If you don't have a way to measure current you can still get pretty accurate. Anyway, play a sine wave through the amp, turn up the amp until you see the output waveform begin to clip, back it down just until you have a nice clean sine wave again. Make a note of the output voltage at this point, also note whether it is peak or RMS. If you are measuring the current also, make note of that reading. If you have measured both current and voltage you can multiply them together to get power. If you have RMS current and voltage, you get RMS power. If you didn't measure current, Take the voltage measurement, square it, and divide by the load resistance. There are more accurate ways to do this involving much more expensive equipment, but this will get you very close.
quote:Originally posted by Mike Peterson: thanks i had a rough stimate but i wanted to be sure i was doing it right.
In case you want resistors : Just found some really cheap ones at www.apexjr.com Look for the 30W, 8 ohm, Dale, heatsinkmountable ones. If you're really gonna measure extreme power, consider putting the resistors in destilled water. (NOT REGULAR TAPWATER !!!!!)
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