(http://www.globalkast.com/images/tonywoodside/Digital_PWM-7.jpg)
This is the Pulsing Circuit fully adjustable from 1Hz - 10kHz. The duty cycle from the 555 chip is 95% and is then inverted by the 7404 to 5% duty cycle. All pulses from 7490 chips are 50% duty cycle.
(http://www.globalkast.com/images/tonywoodside/+5v_+12v_PowerSupply-5.jpg)
This is the Power Supply that provides +5v and +12v to the pulsing circuit. I have this power supply limited to 1A. I'm only using the +5v.