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.

Adjustable Current Limiter LM317 (CB15314E)
The maximum current of this circuit is 1.5 A. The circuit has the formulas next to the diagram to...
Back Up for Solar Cell (CB13545E)
The purpose of this circuit is to ensure that an auxiliary 12 V battery continues to supply power...
Transistorized LC Oscillator (CB24028E)
We found this circuit in the May 1970 issue of Radio Electronics magazine. The maximum frequency...