Found in an EDN from the 90s, this regulator makes use of the integrated circuit of the time. The input can be from 8 to 20 V.
Found in English documentation, this touch sensitive switch must be powered by an isolation...
This circuit was found in a 1969s American documentation. With modern components, it can be used...
With this circuit it is possible to produce RF signals up to a few tens of megahertz using TTL...