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 was found in a European documentation from 1964. The circuit makes use of components of...
This circuit consists of a design improvement that we have previously published (1982), obtaining a new...
This adjustable circuit from 0 to 200 nA was found in a 90's EDN. The components can still be...