This input circuit for meters, which can also be used as a shield, is intended for operation with very low frequency signals. The power supply must be symmetrical.
We found this 3-transistor receiver in the July 1970 issue of Radio Electronics. The transistors may be...
The integrated circuit used in this detector is uncommon today. We found it in a documentation from the...
We found this Japanese commercial radio diagram of three transistors in a documentation of the...