Need toroidal core part number to make a pulse transformer out of it.

Thread Starter

rahul411

Joined Feb 19, 2018
241
So far i have been trying to make a pulse transformer out of the toroidal cores I had, but the results were not that good. With one core i got almost square wave on output but it was not ripple free.IMG_20200218_141555.jpg
This is the output I'm getting and from other cores they are not even close to square wave at output. I don't know the specs of the core im using but i used an online calculator to calculate the permeability of the material and it is 19000. how_to_determine_permeability_of_unknown_cores_online_calculator.html
This is the calculator link. The dimensions are OD=25MM ID=10mm and height=10mm. These is a very small core for the application I have.

http://omapalvelin.homedns.org/tesla/SSTC/general-sstc-notes-gatedrv.htm
This site have very great material to read about making of pulse Transformers and testing them. But the author forget to mention the core part number or the material type or anything about core. This is what he said about cores "specifically those which are used in RF filtering chokes and broadband transformers. EE- and pot-cores don't perform too well." Now I'm wondering how and where to get such core?
I have listing of micrometals cores. Attached below. Which one to choose?
 

Attachments

Thread Starter

rahul411

Joined Feb 19, 2018
241
Also i forget to mention that im using tl494 generating 100khz in push pull configuration, nothing fancy here just hooked a resistor and a capacitor to 494 according to the datasheet. The output of this goes to the amplifier stage made with BD139 and BD140.

IMG_20200218_141214.jpg
This is the values of the wave im getting, if it is useful.
For testing im using the setup mentioned in here http://omapalvelin.homedns.org/tesla/SSTC/general-sstc-notes-gatedrv.htm
 

Thread Starter

rahul411

Joined Feb 19, 2018
241
https://www.fair-rite.com/product/toroids-5975002701/
This is the core I chose to make transformer. But the permeability given here is initial permeability and the author in the pulse transformer design is talking about relative permeability. What is the difference between both? The core (above link) have initial permeability of 5000.
Relative permeability is relative to permeability of materials in vacuum (ie- ratio of both), then initial permeability is the permeability of materials at the initial stage of usage? Then over the period of usage and abuse it's permeability gets lowered? Is it?
 

shortbus

Joined Sep 30, 2009
7,454
This is the core I chose to make transformer.
Didn't learn much from you induction heater did you? Why not use what was found to work from your link? Or at the very least try to cross reference it. Making substitutions, without knowing whether they will work or not is just crazy, at least to me.
 
Top