Touch controlled voltage source (CB22141E)

We found this circuit in an old English documentation. Transistors support modern equivalents.

High speed trigger (CB21850E)
Found in the 1974 Ferranti transistor manual, this Schmitt trigger circuit uses general-purpose transistors...
CMOS 4001 and 4011 Test (CB19073E)
This circuit was developed to test suspect 4001 and 4011 integrated circuits. The circuit is from...
Old power supply (CB23622E)
This power source with silicon diodes at a time when valves were still used was found in Radio...