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 was found in old documentation, but the setting applies to any operational. Resistors...
We adapt this circuit of Radio Electronics - March 1990. The magazine no more exists, but the...
The circuit of the figure consists of a motor timer that can delay drives for up to 15 minutes....