Plant soil heater (CB7964E)

This circuit was found in a 90’s 303 Circuits. The components are from the period and the heating system depends on the resistive element.

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Ultrasonic Transmitter (CB18476E)
This ultrasonic transmitter was found in a 1974 documentation. The receiver is the CIR11753 or...
Electronic Fuse (CB25411E)
This circuit was found in the December 1991 issue of Radio Electronics magazine. The circuit is...
Pendulum Circuit (CB24555E)
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