120_VAC_SINGLE_HETEROSTRUCTURE_LASER_DRIVER_SUPPLY

Published:2009/7/14 11:38:00 Author:May | From:SeekIC

This figure shows the complete schematic of the 120-Vac SH power supply. The circuit consists of a polarized plug, a voltage doubler, a large-value storage capacitor, two neon indicator lamps to show that ac and dc power is present, a 1-MΩ firing-rate control, and the business end of the supply to drive the laser. I2 is also a safety light. When it is on, the laser should be considered operating. The current to the voltage doubler is limited by resistors R1 to R3, and by the capacitive reactance of capacitors C1 and C2. R7-a 47-kΩ, 1/2-W resistor-limits the input power to the avalanche circuit to avoid overheating the diode or Q1. The capacitors and resistors serve to isolate the circuit from the ac line sufficiently to prevent a shock hazard; however, you can still get shocked. Be sure you put this device in a nonconductive case, and obey the polarity of the polarized plug. Don't touch any part of the circuit while it's plugged in, either. Be sure you use a plastic potentiometer for VR1, or a separate control-type potentiometer with a plastic knob.



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