Found in Popular Elecronics, this configuration also appears in this section, but obtained from other sources. The 14.4 V supply allows the circuit to be used in the car.
This calibrated circuit was found in documentation from the 1980s. It makes use of an integrated circuit...
This triac synchronized circuit was found in the July 1995 issue of Electronics Now magazine. The...
This high input impedance circuit makes use of two operational ones that are still common. The...