Photometer for enlarger (CB8342E)

This circuit for old photo enlargers was found in a 1970s RCA manual. The components are from the time, but modern equivalents can be used.

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Mechanical Reverb (CB23788E)
This reverb effect was found in the December 1961 Radio Electronics magazine. It makes use of...
1 to 20 MHz Colpitts Oscillator (CB6506E)
Found on Popular Electronics from the 1990s, this oscillator uses a general purpose transistor. The...
High Pass Filter (CB25602E)
This simple 741 circuit was found in the August 1993 Electronics Now magazine. The source must be...