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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Low cost isolation transformer (CB7973E)
Two identical transformers can be used as a single improvised isolation transformer. The maximum...
Community TV Transmitter (CB18132E)
This transmitter can send its signals from several kilometers away, depending only on the antenna...
Power control (CB23586E)
This circuit was found in Radio Electronics magazine from January 1959. The power transistor must...