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.
One of the first transistor amplifiers with transformerless output but using a 45-ohm speaker. This...
Found in Radio Electronics from the 90s, this circuit uses a thermistor as a sensor that can have...
The circuit presented is from an old magazine having been translated and published in a national...