HELP, I need a transformer

[snipersquad100]

Can anyone please point me to a transformer for this ESR meter project.

[c4757p]

The turns ratio is given because they intend you to wind it yourself.

[snipersquad100]

Has it goto be in a bobbin?

[c4757p]

Look up the core they have specified and try to find a similar one. (I don't have time to check ATM.) A small ferrite toroid would probably do, though 400 turns on a small toroid would be a bitch.

[snipersquad100]

yeh, use the thinnest gauge wire I can find lol

[Bored@Work]

Amidon cores are still available. A simple google of the product number will tell you.

[kg4arn]

If you trust the design, I recommend using the exact core the designer has specified.
Switching cores requires that you have a good knowledge of what you are doing:  frequency range, core losses, saturation. . .

[Mr Smiley]

Hi,

I built one of those a while ago and found that a transformer from one of those CFL's was the same ratio 

There using a transformer to ensure the impedance driving the capacitor is as low as possible.

Also it says 400:20, so would'nt any 20:1 transformer work 

 

[snipersquad100]

Thanks smilly, i think the ratio has something to do with the current handling, not sure thou.

[Icarus]

Maybe you can use E13/7/4. Its tiny and much more easier wind than a toroid.
I strongly recommend to use  bifiliar or trifilar winding. That'll reduce the skin effect.

[Bored@Work]

Maybe you can use E13/7/4. Its tiny and much more easier wind than a toroid.
I strongly recommend to use  bifiliar or trifilar winding. That'll reduce the skin effect.

There is only one problem with this theory. The core in question is an E core, not a toroid. Available for $2.50.

[Jay_Diddy_B]

To the OP, snipersquad100,

Do you your mind set on building this ESR meter?

I have started two threads on ESR meters that do not need a transformer.

This is analog one similar to the one you looking at:

https://www.eevblog.com/forum/projects/5-transistor-esr-meter-design/msg171364/#msg171364

This one can be used with a DMM to get a digital readout:

https://www.eevblog.com/forum/projects/esr-meter-adapter-design-and-construction/msg341177/#msg341177


Regards,

Jay_Diddy_B

[snipersquad100]

The esr meter im interested is this one
He modified the schematic to work with arduino.
Im only building it for fun, I don't expect it to be highly accurate.

[at2marty]

I'm currently working on one that is based off of the same video.  The modifications that I made were to make it "stand alone" rather than a shield that goes on an Arduino.  I also added in serial port capability for debugging and an ISP header for programming modifications.  I also re-wrote the source code in plain C.

The transformer that I selected is an audio transformer available from Radio Shack part number 273-1380.  I believe that it will work correctly, though it's a bit tall and will be close when I mount everything into the enclosure.

I just ordered some boards and should have them next week.  Once I do some testing to make sure that it works the way that I anticipate, I will gladly release the source code and the design files.  I used EagleCad for the schematic and board layout.

[snipersquad100]

hi at2marty
Any luck with your esr meter?

[snipersquad100]

Cant get any voltage out of c2, im using a 10uf cap. theres 2.5v going in but nothing going out to the transformer.