# ETD 49 TRansformer Calculation

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#### Gapoo

##### Junior Member level 1
Dear All,

I have following issues in SMPS Inverter.

• I am making a 1KVA system.Is ETD-49 enaugh for 24V to 350V DC-DC Boost Converter working @ 40KHz Push-Pull ?
• What are the steps to calculate number of turns for high frequency transformer ?
• How to calculate guage of wire ?

Regards
Gapoo

#### FvM

##### Super Moderator
Staff member
I suggest to try the ferrite tool, downloadable from epcos.com

#### fethiyeli

##### Full Member level 4
http://schmidt-walter.eit.h-da.de/smps_e/aww_smps_e.html you can use this web-site. According to it, it is suitable to use. Also you can read little bit the book of tranformer and inductor design 3rd edition. It teaches great. Moreover, when input and output voltage difference is great, suggested topologies are push pull, half bridge or full bridge according to your desired power level.

Last edited:

##### Advanced Member level 4
What is the material of the core like PC40 or what?

#### shatruddha

##### Full Member level 2
• I am making a 1KVA system.Is ETD-49 enaugh for 24V to 350V DC-DC Boost Converter working @ 40KHz Push-Pull ?
• What are the steps to calculate number of turns for high frequency transformer ?
• How to calculate guage of wire ?
Hi Gapoo
ETD-49 is good enough to use for a 1KVA system. I myself have used it quite a few times with N97 and 3C95 cores.
For calculating the number of turns, you can follow these sites
http://www.mag-inc.com/design/design-guides
http://schmidt-walter.eit.h-da.de/smps_e/trafo_hilfe_e.html#d-HFT
http://users.catchnet.com.au/~rjandusimports/formula_1.html

There is a very good video that I find over youtube for HF transformer design

you only need to decide the core and delta B. Rest all can be calculated using the formulae given on these webpages. If you are not sure about Delta B, Just choose it anything between 0.1-0.3 Tesla and do your calculations.

To calculate the gauge of wire, you just need to know how much current is going to flow through that wire. Then Cross section of wire is given by I/J where J is the current density. You can assume it to be around 4 for copper.

Hope this solves your problem