This biestable vox circuit was found in an old documentation. The circuit makes use of components of the time (80's) and can work as a shield since the power is 5 V.
This high-precision circuit was found in a 1969 documentation. The components are from the period. R1...
The circuit shown is a commercial electronic voltmeter sold in Japan in the 1960s. The circuit is fully...
This circuit that uses two LDRs as sensors was found in Radio Electronics magazine from November 1961....