This amplifier step for small signals can use any general-purpose transistor like the BC548. The circuit can be powered by voltages from 6 to 12 V.
This circuit indicates a digital value through a moving bar. The circuit is TTL and must be...
Varactor diodes are our varicaps of today. This circuit for switching signals in an RF circuit was found...
We found this circuit of a clamp-type ammeter in a Japanese documentation from the 1960s. The...