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.
In the figure we have the way to make the three-phase control of a motor using opto-diacs. The circuit is...
We find this simple musical instrument in a 1977 Radio Shack documentation. The key resistors must be...
This circuit was found in General Electric documentation from 1966. The circuit is suitable for any...