Thanks a lot Guyz.... u guyz rock!. Sorry 4 my long absence, am coming work with school so time is more of a serious issue. Av made the circuit using SG3525 oscillating at 80khz, all seemed but i tried quite a couple of ir2110, 2112....all failed, couldn't get a genuine part. I resorted to "Old school" to drive my irf3205 FETs, i used D882 & B772 with emitter resistors of 4.7R and base resistors of 100R for drivers, a Gate resistor of 10R to fets. To keep "Zap" low, I decided to start off with small Core of 75W with a Ac=0.4cm. My input voltage is Vmax=15V, Vmin=10V, Npri-6T. I made the secondary to have three Voltages: 6V=3T,15V=9T,18V=11T. The system started up, without smoke, Zero Noise ....all wer kool.
Woooooooow.... I took a 12mins Dance.
Hahahahaaaa.....First trial without smoke.
I picked my feedback from the 6V point as i shunt it with a 1k resistor to ground, The secondary and primary shared the same ground, I thought it wouldn't matter much since no lethal voltage is present, though I have 2200uf capacitor on the FETs ground and transformer primary centre tap.
Now the problem....
With proper feedback finetune....all sec voltages were good....but as the Battery voltage starts to drop, the secondary voltages starts to increase at a rate of 10mV battery drop to 100mV secondary voltage increase. I can't figure out wer the "Jiggy" is coming from. I thought it wise to consult mi guardians Before I start suspectin a counterfeit SG3525.
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Happy New Year to all My Very Good People of EDABOOARD....God's Blessings this year I pray!