This 10 A solid state relay was found in a 1980s documentation. It can work as a shield and implemented with modern equivalent transistors.
This programmable sound circuit was found in the July 1978 issue of Radio Electronics magazine. It uses an...
In the figure we have an interesting protection bridge against power polarity inversion of a...
Found in 1980s documentation, this amplifier uses a symmetric source and the gain is given by the...