This circuit was obtained from an Electronic Design from the 90's. The circuit generates signals at a frequency determined by R and C. The selection by the jumpers determines the PWM modulation.
The filter shown in the figure, suggested by National Semiconductor, only allows frequencies above...
This circuit triggers a warning oscillator if you forget the lights on when you leave the car. The...
This general-purpose two-transistor circuit was found in the November 1993 issue of Electronics Now. The...