This amplifier with old germanium transistors is from a 1957 documentation. The power is a few hundred milliwatts and the transformers are common types of driver and output of the time.
A ring and pendulum of stripped wires form the sensor for this alarm. Once triggered, to reset, you...
Designed for the audio track, this circuit was found in a Popular Electronics from the 90's. Other...
An interesting basic circuit for projects is shown in the figure. It consists of a digital...