This transformerless circuit was obtained in a 1965 publication by Ferranti. The components are from that time, with emphasis on the type of engine used.
This circuit is from Popular Electronics from October 0, 1981. The diodes can also be 1N4004 and...
This switch or band selector for receivers was found in a Popular Electronics from the 1990s. The...
This circuit, published in 1978, can use any general purpose NPN transistor such as the BC548 and...