This alarm circuit with NC sensors in series was taken from an article in Radio Electronics magazine from May 1971. The SCR can be any of the 106 series.
This circuit is a telephone line simulator and can be used for internal communications. It is...
This digital didactic digit counter uses common TTL integrated circuits and a common anode...
This reflectometer or standing-wave ratio meter (SWR) was found in a 1980s American documentation. The...