This circuit for an optical audio link using LED or LASER was found in a 90s QST magazine. The circuit can use operational amplifiers like the 741.
This circuit can be used as a shield as long as the power is supplied with voltage equal to that...
This simple megaphone is from old documentation, but uses still current components. The circuit is...
This simple telephone amplifier can be used as an auxiliary amplifier for additional listening, without...