This is an amplifier circuit intended for modulating transmitters. The 5-tube circuit is from an American manual from 1947. The power supply uses a transformer.
This configuration is from a 1964 US documentation valid for any FET. The range of power voltages...
This circuit activates a buzzer when the voltage applied to the input falls below a preset value in...
The purpose of the circuit shown in the figure is to open and close the contacts of a relay...