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.

Varicap Frequency doubler with (CB4107E)
We find this circuit in American documentation from the 1980s. It consists of a frequency folder...
Flip Flop with the Operational LM3900 (CB4510E)
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We...
Divide-by-5 Using the 4018 (NI005E)
One pulse in the output is produce at each 5 pulses applied to the input. The circuit uses CMOS...