Flyback transformer Turns canculation and gap length

[phobos1]

I read about designing flyback transformer desing from abraham pressman book I have ungapped ferrite core how can i get the required primary inductance. someone tell me how can i determine the gap length and number of turns.

 

[goldsmith]

I read about designing flyback transformer desing from abraham pressman book I have ungapped ferrite core how can i get the required primary inductance. someone tell me how can i determine the gap length and number of turns.

Hi phobos1
If you've followed the Pressman book then you would know that it deals with gap calculations too . page 135 . 137 ,138 , till 145 ! But in fact , most of the times i prefer to use 1 mm as gap , but if my current is going to be high , i increase the gap . ( using experience and trial and error instead calculations of gap ! )

I have ungapped ferrite core how can i get the required primary inductance

Pressman's book has some design examples . you can see them . ( as you mentioned you have access to this book so you can read it's design examples ) . and also marty brown's book has some design examples . and there are many application notes and design ides in google . did you try to search for them ?
Best Wishes
Goldsmith

 

[phobos1]

Thanks goldsmith i'll try with this

 

[phobos1]

Hi gold smith i got my flyback transformer running but the primary current keeps increasing by 1ma step slowly is it right

 

[goldsmith]

Hi gold smith i got my flyback transformer running but the primary current keeps increasing by 1ma step slowly is it right

Hi phobos1
What do you mean by running by 1 ma step slowly ? is that mean that when you have putted the load across the output , then the current is not in the value that it should be ? and then it is increasing as steps ? or perhaps i've misunderstood your meaning ? more information is required .
By the way can you show me your schematic ? perhaps you have used a current limiter for that and it is improper ? are you using a current mode flyback converter ?

Best Wishes
Goldsmith