We found this circuit in Radio Electronics from the 90s. The components are current. The sensor is a common general-purpose transistor. The connection to the sensor is made by twisted pair.
This circuit has been obtained from a technical documentation on filters from 1977. The...
Figure Bellow shows how to use a 7490 (TTL) IC to divide the frequency of a TTL signal by 6; The...
Found in a 1969 Burr-Brown publication, this circuit makes use of integrated components from that...