We found this circuit in a spy book from the 90s. Transistors admit equivalents and the coil can be designed as in the CB19425E project. Power is provided by cells or 9 V battery.
This circuit with the PA7601 was found in a 1967 Philco-Ford documentation. The circuit has a pass...
This CMOS version of the force gauge was found in a 1983 publication. In the CMOS version, the...
Using the LM317 (or LM350), this circuit is based on precision regulatory components such as those...