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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Full wave dimmer (CB7208E)
Found in Motorola's 1965 manual, this full-wave dimmer controls a load that depends on the used...
Linear Summing and Differentiating Circuits (CB20147E)
The two adding and differentiating circuits with operational amplifiers given below were obtained from...
Digital Windshield Wiper Timer (CB24567E)
This sophisticated circuit was found in the November 1978 issue of Radio Electronics magazine. Based on...