This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms and excites a load of 16 ohms. The integrated circuit of the time is the PA237.
Found in a 1995 Hands On-Electronics, this circuit generates a sinusoidal signal whose frequency...
This circuit makes use of an optical coupler to isolate the telephone line. The circuit is from...
Upon pressing the switch, the circuit generates a pulse whose duration depends on C. The...