Tape preamplifier (CB20575E)

With NAB equalization we found this circuit in an English documentation from 1967. The transistors used are germanium types of the time.

Audio Voltmeter (CB1441E)
The purpose of this circuit, which we find in a 1975 radio amateur publication, is to measure the...
Active crossover (CB949E)
We find the original circuit in a technical publication of 1978. Changing the components, such as...
Two-Transistor Old Flip Flop (CB949E)
This circuit was found in a 1958’s publication. It uses germanium transistor, availble that time....