This circuit was found in a 90s Popular Electronics. The circuit uses components from that time, intended to receive signals in the range of 150 to 250 kHz.
This circuit can be found in a 1970 Motorola documentation. The circuit can be implemented with general...
This shield circuit with an optical coupler was found in an 90s EDN. The circuit can be used with...
This circuit is from 1977 documentation, and high current equivalent transistor must be used. The...