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.
This circuit takes advantage of the inductance of the coil of a high-impedance phone to form the...
This circuit controls a fan in the car, according to the temperature, activating it automatically when the...
In relation to the previous circuit (CB18493E) this spy has an extra transistor, which can be a...