Linear photometer (CB7366E)

This circuit was found in a 1967 Philips publication. Transistors support equivalents and modern equivalents can be used.

12V Battery Charger LM350 (CB4845E)
This circuit consists of a constant current source for charging 12 V batteries. The charge is...
Neon Power Monitor (CB24103E)
This simple neon lamp power indicator circuit was found in the January 1971 Radio Electronics...
Harmonic Distortion Meter (Cb23613E)
We found this sophisticated meter circuit in an article in Radio Electronics magazine from June...