This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time. The circuit is from the 90's, not being given the power supply.
This circuit, which has a very common configuration, was obtained in a 1994 documentation. It can...
This power control was found in a 1968 power circuit manual. The SCRs are according to the power of...
This traditional crystal radio circuit was obtained from a 1990 documentation. The diode can be...