We found this circuit in a 1977 National Semiconductor Databook. The circuit can use other FETs like the BF245 and has an input impedance of 10 megohms. The circuit gain is unitary.
This control is intended for 110 VAC or 220 VAC Motors. Any TIC series triac can be used according the power...
This 1965 General Electric circuit uses a "Thyrector" that is a suppressor of the time. The...
The S-meter is a signal strength meter used in communication receivers. This circuit was found in...