Using transistors at the time, this circuit was found in a 1967 Ferranti documentation. The circuit is for 150-ohm transmission lines.
This fast converter using operational was found in a 70s American documentation. The circuit can be...
This transmitter for the 80-meter band (3.5 MHz) was found in an old documentation for radio...
This touch switch appears elsewhere on this site from various documentation. This is from an 80's...