This commercial circuit is from a Japanese magazine from 1967. It uses germanium transistors, and the coil can be made with 80 to 100 turns of fine enameled wire on a ferrite rod.
November 2016 - Texas Instruments' new TLV8802 nano-power operational amplifiers for wireless...
We found this circuit in a documentation from the 70s. Semiconductors are from the era and can be...
The circuit shown in the figure is a voltage follower, that is, an amplifier with unit gain. The...