Analog to digital converter (CB20538E)

This TTL circuit for PC was found in an English documentation from 1992. The integrated circuit used ZN426E is not in common today.

5.5 W amplifier - LA4420 (CB981E)
The circuit presented uses an integrated circuit Sanyo, not very common in our day. This amplifier provides...
SIDAC surge tester (CB4246E)
This surge test circuit was found in a 1980s ON Semiconductor documentation. The circuit makes use...
Heterodyne Mixer (CB4291E)
This is a typical 80's FM radio mixer circuit. The circuit was found in a documentation of the...