This shield circuit, from a documentation from the 70s, employs an optocoupler with two SCRs to control a small load of 1.5 W.
This three-transistor circuit was found in Radio Electronics magazine from May 1969. The circuit is...
This beat frequency oscillator was found in a 1980s documentation. The original FET has a grounded...
With this circuit it is possible to make the selection of transistors and their test according to the...