This circuit is the receiver for the previous transmitter modulated by an audio signal. The transducer is a ceramic capsule, in which case the circuit becomes ideal for telegraphic transmissions.
Found in American documentation from the 1970s, this circuit is intended for amplifying analog TV...
Photoelectric cells can be used as sensitive light sensors. However, the low voltage they generate...
This circuit was found in a 90s American documentation. The circuit uses still common components...