This interesting circuit uses a sodion valve that we have already described in an article on the website. The circuit uses several batteries for power. The phone is of high impedance.
The purpose of this circuit is to automatically turn a water pump on and off. Sensor 1 is the...
This circuit was found in Motorola's 1967 documentation. The circuit makes use of power...
This interesting circuit appeared in the April 1952 Radio Electronics magazine. The circuit is...