We found this circuit in a 1960 Radioarama magazine. The instrument tests common general-purpose transistors indicating their gain on a moving coil instrument. The loop serves to adjust the circuit.
This circuit was found in 80's Popular Electronics. The components used are common and the number of...
The 556 integrated circuit is a double 555. The heats of the components depend on the frequency and the...
This 18 V x 300 mA power supply was found in a 1969 documentation. The integrated circuit is...