This preamplifier for phonographic capsules using FET was found in 90s American documentation. Consumption is very low. The power can be obtained from the amplifier circuit with which it works.
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...