Found in an American publication from 1969, this circuit can be adapted to be used as a shield. Operational amplifiers can be of modern equivalent types.
This preamplifier for the phonographic capsule was obtained in an Argentine publication from 1973....
This wireless intercom has a range of about 300 meters using an integrated circuit that is not...
This circuit was found in a Hands On Electronics from the 90s. The circuit does not need a...