Hi there,

I built a high frequency transformer:

• f = 80kHz (square wave)
• 15 primary turns, 45 secondary (turns ratio 3)
• Ferrite core

All my calculations tell me that I'm not loading the source or saturating, but I get strange waveforms on the primary and secondary.. I can't seem to post the image (too big), but the positive plateau slopes downwards and the negative upwards. It does a little kink at each transition. What's going wrong and how do I fix this?

Thanks

 

Is that a halfbridge? If you can´t post images here, post it for example on imageshack a put here the link.

 

There are a gazillion free programs out there to resize pictures for you. IrfanView is one.

 

It's an inductor. What makes you think anything is wrong?

 

Hi there,

I built a high frequency transformer:

• f = 80kHz (square wave)
• 15 primary turns, 45 secondary (turns ratio 3)
• Ferrite core

All my calculations tell me that I'm not loading the source or saturating, but I get strange waveforms on the primary and secondary.. I can't seem to post the image (too big), but the positive plateau slopes downwards and the negative upwards. It does a little kink at each transition. What's going wrong and how do I fix this?

Thanks

It sounds as if the primary inductance is too low. Do you know the Specific Inductance (Al) value of the core?

The inductance is given by L = N\(^{2}\) * Al , so with N=15 you would have L = 225 * Al.

 

Right enough, how important is it to preserve flat tops and bottoms anyway - and for that matter, how much tilt are we talking about: 10%, 50%, or what?

I think you are going to need to get to grips with posting images.