This circuit is from a 60's documentation. The circuit uses components from the era and serves to monitor a 150V continuous power line.
This circuit can be used to measure the frequency of a low frequency square signal. The signal can be...
This 80's circuit turns off a TV or other appliance after a set time. The base is a 555 IC and the...
This circuit uses indicator lamps, as it was obtained from an American publication of the 90s. The...