This 1924 receiver uses a battery for the tube filaments and a high voltage battery for the amplifier and detector circuit. The speaker is kind of high impedance era.
This circuit was found in 1980s Radio Electronics. The circuit includes the power supply. The...
This circuit was found in a former Popular Electronics. The timing is set on the potentiometer and the...
This circuit has appeared on our site several times as a battery status monitor. In this...