555 Code Oscillator (CB26324E)

Found in a 1990s Popular Electronics, this circuit produces a tone on a small speaker. The keyer directly controls the power supply.

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Experimental Optocoupler (CB12204E)
With this circuit it is possible to demonstrate the working principle of an optocoupler. The LEDD...
Logarithmic Wattmeter (CB13664E)
This circuit was obtained in a documentation for radio amateurs in 1974. The coil consists of 12...
Negative Voltage Generator (CB25844E)
This very low power circuit is based on the ICL7860. We found it in an Electronics Now from April...