Hi guys,
I have recently built a class AB power amplifier for the LW/MW band and am in the process of testing it. However I am having
some doubts with respect to the power delivered to the load (250W 50 ohm dummy load). My question is, if I measure
the RMS voltage across the (purely resistive) load, and the shape of the wave is a sine wave at 400 kHz, can I
also assume that the true rms power is given by Vrms^2 / Rload, as with lower frequencies ? Or should this be confirmed
with current measurement, taking into account power factor or something else? The waveform is attached below - the red trace is at the gate of one of
the transistors, and the yellow trace is measured across the load. Vk is the RMS
voltage. I don't know if I'm supposed to measure something else so I'm happy to hear if anybody has some advice, thanks.
I have recently built a class AB power amplifier for the LW/MW band and am in the process of testing it. However I am having
some doubts with respect to the power delivered to the load (250W 50 ohm dummy load). My question is, if I measure
the RMS voltage across the (purely resistive) load, and the shape of the wave is a sine wave at 400 kHz, can I
also assume that the true rms power is given by Vrms^2 / Rload, as with lower frequencies ? Or should this be confirmed
with current measurement, taking into account power factor or something else? The waveform is attached below - the red trace is at the gate of one of
the transistors, and the yellow trace is measured across the load. Vk is the RMS
voltage. I don't know if I'm supposed to measure something else so I'm happy to hear if anybody has some advice, thanks.