Power pulser is uses a low-frequency oscillator to drive a voltage regulator. As shown in the circuit, using the timer chip LM555 (IC 1) is wired as an as table multi vibrator. Components R1 and R2, VR1 and C1 produce the frequency. If you can vary the frequency level means you can adjust the Potentiometer VR1.
The output of IC1 at pin 3 controls the switching on/off of adjustable voltage regulator LM317T (IC2) through npn transistors SL 100B (T1) and it can be used for incandescent lamps, DC motors, electromagnetic relays and LEDs. You can use the input power supply of 5V-18v, 1.5A and adjust the output to 1.25V-15V, 1.5A, after selecting the load , power up the unit with switch S1 in ‘on’ condition. Currently, connect a digital multi meter across the output terminal of IC2 and set the output voltage using potentiometer VR2.
Frequency setting through VR1, produced switch S1 is ‘on’ with 18V DC input, and maximum output voltage is approximately 15V.you can select the as table multi vibrator frequency value by using range of components R1, VR1, R2 and C1 according to your requirement. To connect switch S1 and LED1 on the side of the cabinet and fixed potentiometers VR1 and VR2 at the bottom of the front side, fix the input and output terminals on the front side cabinet. Using external swires connect the power supply to the input terminal and the load to the output terminal.
