14 Watt Compact Fluorescent Electronic Ballast

This circuit came from a 14 Watt Commercial Electric spiral bulb from Home Depot. In fact, I drew it in that way because it was layed out very well, so much credit should go to Sam Goldwasser. It is a rather interesting oscillator circuit which I will attempt to explain the operation of. However, I don`t fully understand it, so if someone else doe
14 Watt Compact Fluorescent Electronic Ballast - schematic

s please contact me at the above e-Mail address so that the aspiring electronics experimenters who visit these pages may expand their understanding. On the other hand, if I got it right, also please tell me, or if you have anything to add to the explanation. As the power comes in, it is filtered by L1 and a. 1uF capacitor. A. 47 Ohm reisitor is also provided and is probably fusible. It is then rectified by the bridge formed by D1-D4 and filtered by a 10uF capacitor. As power is first applied, a 100nF 63V capacitor begins charging through a 470k reisitor. Once this capacitor reaches 32V, the DIAC breaks over turning on Q2. Power then flows through Q2, the top winding of T1, L2, a filament of fluorescent bulb FL1, a 4. 7nF capacitor, the other filament of FL1, and a. 1uF capacitor, current being limited by L2 and the resistance in the filaments. Transformer action also begins inducing power in the other 2 windings of T1. This tends to begin to turn on Q1 and turn off Q2. Once Q1 is on, the charge that has built up in the. 1uF and 4. 7nF capacitors attached to FL1 begins flowing back the other way through the filaments, L2, the top turn of T1 and Q1. This once again induces power into the other two windings of T1 except in the opposite direction, eventually turning off Q1 and turning on Q2. The 470pF capacitor and other 470k resistor apparently make sure that both transistors are not on at the same time. Otherwise, it would be...

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