This circuit is for traditional old-style telephone lines found in an American 1980s documentation. Components are common and the optical coupler can be replaced with an equivalent.
Depending on the components, given in the table, this circuit can amplify signals of 100 MHz or...
In this circuit, the relay remains closed by activating a lamp, for a time that depends on the...
This 6-transistor Japanese commercial radio was manufactured in the 1960s. The receiver is a super...