Chess game timer (CB7084E)

This RCA circuit provides timing intervals from 5 to 120 seconds. The components are of the time, but they admit modern equivalents.

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TTL Optical Interface (CB16022E)
In the figure we have a Texas Instruments circuit for TTL interfacing using discrete transistors. The two...
Remote control tunnel transmitter (CB23885E)
This circuit was found in Radio Electronics magazine from June 1963. The range is small and the...
50W 40 Meters RF Amplifier (CB17683E)
The project presented in a 2009 documentation is intended for radio amateurs operating in the...