This circuit is from the Linear Applications Handbook of the National Semiconductor of 1994. Transistors are common, but the integrated circuit is not easy to obtain today.
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...