Recommended for automotive applications, this circuit was found in an April 1982 Radio Electronics magazine. The transistor supports equivalents. Sensitivity adjustment is made by R1.
In the original 2000, this circuit was designed to interface the parallel port with external...
The author has many books he had written in Eglish (See the Biography) published by famous...
This circuit, to add the ambience effect, was suggested by National Semiconductor in documentation...