5 years ago
@ 16:15 of your explanation: You seem to indicate that scopeing the center tap (which is hooked directly to ground) of the transformer will show you the bottoms of the AC waveform. I guarantee that scoping anything directly hooked to ground will only show 0 VDC and 0 VAC, unless there is something seriously wrong in the circuit. If you want to see the bottoms of the waveform, scope each plate of the tube. When it is reverse biased, you will see your waveform bottoms, which the tube is conveniently blocking for you. Scopeing the filament
would show the positive waveforms from both halves of the tube, but you will see that waveform smoothed by any filtering capacitors on the B+ line. So it will be more or less a high DC voltage, with some ripple. You will not see the sum of the positive voltage waveforms, the filter caps will swamp that out.