This circuit was found in General Electric's 1965 documentation. It appears elsewhere on the site. The SCR and the diodes must be in accordance with the motor current.
Found in a 1968 EEE, this circuit accepts frequencies from 1 to 1000 Hz and control voltages from 0.1 to...
This circuit was found in the January 1989 issue of Radio Electronics magazine. The circuit sends...
This circuit with silicon transistors at the time was found in the Radio Electronics magazine of...