This traditional dimmer configuration for incandescent lamps and heating elements was found in an RCA transistor manual. SCR can be a more modern equivalent like TIC106, depending on the power grid.
This circuit for common analog telephones was found in March 1982 Radio Electronics magazine. It...
We found this circuit in an English publication from the 1980s. The transistor can be BC548 or...
Found in a 1967 RCA documentation, this circuit can be made with equivalent SCRs according to the...