This circuit, found in a 1977 documentation, indicates when the grid voltage goes through zero. Under these conditions, it produces an output pulse whose duration depends on the capacitor.
This filter rejects 1 kHz signals, being suggested by the manufacturer of the operational...
This is a simple variac type source found in the July 1962 Radio Electronics magazine. Voltage and...
The current of this source is 200 mA at the most, and the output depends on the zener that may...