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Ask help about a ballast circuit for fluoresent

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bhl777

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Hi all, I saw a ballast circuit for fluoresent like the one in the attchment, but when I built it on the breadboard, it cannot make the fluoresent light. If the inductor is fine and there is no problem of the transformer and BJT, should I change something in the configuration? Chould you tell me what I should do to make it work well? Thank you so much!
 

I saw a ballast circuit for fluoresent like the one in the attchment
Click to expand...
What did you saw? An operating circuit? Or a schematics, that was said to work? It doesn't work as shown, for several reasons.
1. The feedback polarity is wrong.
2. It misses a startup circuit
3. A base current can only flow by breakdown of the opposite base-emitter junction.
4. There's no explicite current limit for the base current, so it depends on the transformer dimensioning (e.g. winding resistance and leakage induction), if the circuit will survive the first seconds of operation.

P.S.: If the said faults would be corrected, the circuit still needs meaningful winding ratios. How do you intend to find them?
 

HI

This circuit is a push pull resonate type oscillator it use the transformer 2nd coil create a positive feedback neccery for oscillation

Check the type of trnsformer you have used - most of probelm with this type of circuit came from trnsformer

All the best

Bobi
 

FvM said:
I saw a ballast circuit for fluoresent like the one in the attchment
Click to expand...
What did you saw? An operating circuit? Or a schematics, that was said to work? It doesn't work as shown, for several reasons.
1. The feedback polarity is wrong.
2. It misses a startup circuit
3. A base current can only flow by breakdown of the opposite base-emitter junction.
4. There's no explicite current limit for the base current, so it depends on the transformer dimensioning (e.g. winding resistance and leakage induction), if the circuit will survive the first seconds of operation.

P.S.: If the said faults would be corrected, the circuit still needs meaningful winding ratios. How do you intend to find them?
Click to expand...



Thank you man, I think the schematic is just tell me how to do this but it is not the total one. could you draw a schematic to show me how to improve this one?
 

bobcat...actually this is not resonant,....that seondary cao is solely for DC Blocking....pse see

**broken link removed**
 

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    bhl777

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