This circuit was found in the September 1992 issue of Radio Electronics magazine. The circuit does not use a transistor to drive the relay and has no adjustments.
This dual-tuned 60 Hz oscillator was found in the Radio Experimenter Special projects of 1993. The...
This SCR thermostat circuit was obtained in a technical documentation from the 1980s. Some...
This circuit is more elaborate than the previous one. It was obtained from an 80s circuit manual. The...