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.

| Clique na imagem para ampliar |

Signal Tracer using the 741 (CB1533E)
This circuit consists of an audio signal tracer using two 741 operational amplifiers. The output...
MW Experimental Radio (CB4517E)
This circuit was obtained from a 1964 magazine and has some interesting features such as the input...
Short Circuit Protection for the Bench (CB3821E)
This circuit uses a contactor having been found in a 1987 publication. More modern equivalent...