This circuit, obtained from old documentation, doubles the frequency of the pulses applied to the input. The circuit must be powered by a voltage of 5 V.
The circuit presented was suggested by a Texas Instruments optoelectronics manual. The voltage...
This cassette player motor speed control was found in the January 1991 issue of Radio Electronics...
This is an old circuit with a homemade sensor found in the September 1995 Electronics Now...