Suggested by an American documentation from the 90s, this circuit generates signals with frequencies determined by the capacitors and calculated by the formula next to the diagram.
This narrowband data receiver is from the Philips Databook of 1990. The circuit is powered by 5 V...
This circuit was proposed by an old American documentation for listening to SSB stations. The...
This voltmeter for continuous voltages has several scales and is totally passive. The diodes are...