Design Notes - Power Electronics - 03

The Voltage ramps up in the sine wave which gives a near "Linear" slope which can be used to trigger the ON at a time delay after zero crossing when the voltage is zero. This is like a PWM but works on low frequency only. Some of the early SMPS(HV for TV and Mains Inverter) by Siemens were built around SCRs. Turning off a SCR is a difficult job for a designer, MOSFETS and IGBT are now used for PWM drive stages.
High Energy Circuits
You can use it with a bulb to vary brightness of bulb, this is a live circuit it can give a shock, enclose in plastic box, the pot should have a plastic knob, use a fuse, you can also use it for temperature control of soldering irons.
The Source file in CadSoft EAGLE format is here del00004.zip