This circuit has a frequency range of 30 Hz to 100 kHz with an output signal of 1 Vrms. We found it in 70s American documentation. The integrated circuits are CA3140.
Using a 4017 as a base, this circuit from a 1990s Popular Electronics generates low-frequency...
Approaching the hand or an object to the sensor of this circuit, the relay closes its contacts. The...
This 1967 General Electric circuit makes use of an array of 3 (integrated) transistors for an...