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20 : 1 Transformer.

kieferatkin

Hi Everyone,

 

Do any of you know of a good 20 : 1 turn ratio transformer that can change 5v down to 200mV ~ 300mV at 100 KHZ?

 

It is for my Arduino ESR Meter i am building.

 

Looking forward to any positive response.

 

Cheers image

  • 0

    there are a few ESR projects for the Arduino on the internet already, have you found them for review yet, worth a look ie: http://forum.arduino.cc/index.php?topic=80357.0

     

    I am not sure why you need a transformer (It would be a pulse transformer at that frequency btw). The testing I have played with in the past is to use the Arduino ADC directly and have a resistor divider to ensure any voltages are in the range of the ADC. but from my recollection, often ESR meters are also usable in circuit and therefor have to use voltages less that about 600mV in order to not turn on most diodes or other semiconductors

     

    the idea being that you inject a pulse of known  current and measure the volt drop across the device under test while the pulse is being applied. As long as you do this quickly after the pulse is applied you will be able to deduce the effective resistance as the capacitance has not yet come into play by charging and therefor changing the virtually instantaneous voltage across its internal resistance

     

    a perfect capacitor (If one ever existed) would have no voltage drop and therefor no series resistance. ( Couple this with the perfect power supply also with zero internal resistance and the draw would be infinite current and the world would come to an end as we know it lol)

  • 0 in reply to Robert Peter Oakes

    @Kiefer  Generally I agree with Peter but if you really need a transformer you can have fun and learn good stuff by winding your own.

     

    If you decide to go that route ask again and explain the spec you need and I'll tell you how to do it.

     

    MK

  • 0

    Thank you Peter and Michael  for replying to my post.

     

    I never thought of making my own transformer so i will defiantly give that ago sounds like a lot of fun image

     

    The reason that i asked this question was because i found a video on you tube by a guy called Dennis hill in which he managed to make a shield for the arduino

    using the following schematic on this website: http://ludens.cl/Electron/esr/esr.html and the circuit used is based on a design by Manfred Morninweg. i knew where to get the other parts from but i was having some difficulty in understanding what transformer i needed to obtain as he found the correct one from a salvage op.

     

    Here is a link to the video's: https://www.youtube.com/playlist?list=PLoy_rdbzLRuCn0v_cDybiZzq6jyCmWr5p

     

    it is really interesting and i will give both ideas ago.

     

    Thanks again for the replies image

     

    ill keep you both informed of my progress.

     

  • 0 in reply to kieferatkin

    I look forward to it, if you get into difficulties you know where we are

     

    Have fun