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.
Found in an Electronic Design from the 90's, this circuit uses common components. The circuit is...
When the sensor receives light, the relay closes its contacts and remains so even after the light...
This circuit produces pulses of 90 V at intervals that can reach 5 minutes. The circuit is from a...