This circuit with junction field effect transistors was found in documentation from the 1980s. The transistors can be MPF102 or BF245 and details of the coils are not given in the original.
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...