Signal Tracer and Capacitor Tester (T1241E)

This mains powered two-in-one instrument was found in a Radio Craft from March 1948. The headphone must be high impedance.

700 mW amplifier with LM386 (CB966E)
This is one of the many versions of amplifiers with LM386. This was achieved in an old publication (1981). The...
5-Step Sine Wave Generator (CB24476E)
The figure shows how to generate a sinusoidal signal using 4 flip-flops. The circuit is from a...
Automatic Switch 110 V 220 V (CB17313E)
The integrated circuit, in this 1986 application, is not a very common component today. The...