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Reducing voltage

Discussion in 'General Electronics Discussion' started by dandan, Feb 4, 2013.

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  1. dandan

    dandan

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    Feb 4, 2013
    Hey Folks, I have a microscope that came out of an elementary school that requires that I reduce voltage from 110 to 65. 2 questions. 1, is this just for the light that is attached and 2, can I just splice in a standard house wire dimmer switch to accomplish this? Thanks for any and all replies. Dan
     
  2. dandan

    dandan

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    Feb 4, 2013
    Ps, I don't have the other half of the plug, just the 2 male prongs in the attached wire from the unit.
     
  3. davenn

    davenn Moderator

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    Sep 5, 2009
    hi there, welcome to the forums

    I would suggest that it would be a bit dangerous to use a dimmer
    You really should use a transformer to from the voltage down to 65V

    This gives you isolation fom the mains voltage if any fault should develop with the wiring or a dimmer and the microscope chassis becomes live at mains voltage

    Consider the consequences of putting your eye up to the eyepiece in those conditions and getting mains voltage zapped through the eyeball etc

    Dave
     
    Last edited: Feb 5, 2013
  4. dandan

    dandan

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    Feb 4, 2013
    Thank you Dave! The only other question I would have would be, would plugging it into a power surge strip alleviate this danger?
     
  5. davenn

    davenn Moderator

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    Sep 5, 2009
    no it wouldnt as its still supplying non-isolated mains voltage
    a transformer is the only way to provide the isolation

    dunno what country you are in ?
    if the USA then try radio shack, digikey, mouser for an appropriate transformer

    D
     
  6. dandan

    dandan

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    Feb 4, 2013
    Ok, I've been educated. Don't do anything stupid Dan! I did check radio sahck and and they said "Uuuuhhhh....." so i came to you. There is one on E bay, but I'm a cheap so and so, not stupid. ; ) E Bay it is! Thanks very much! Dan
     
  7. CocaCola

    CocaCola

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    Apr 7, 2012
    Are you sure of the specifications, 65V seems like a real odd voltage for a microscope bulb... While 6.5V is quite common...
     
  8. dandan

    dandan

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    Feb 4, 2013
    I think your right Dave. My eyes aren't that good anymore, hence the microscope!
     
  9. CocaCola

    CocaCola

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    Apr 7, 2012
    If it's 6.5 Volts what we would need next is the bulb type or bulb specification so that we know what kind of current you require... Brand and model of the microscope might be helpful in this regard if you don't want to crack it open and take a look at the bulb itself...
     
  10. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Nov 28, 2011
    I would just use a small switching power supply. These are available with a 6V DC output. Look on eBay, you're sure to find something cheap and Chinese there! You might even be able to find one with adjustable output voltage so you could get exactly 6.5V for perfect bulb brightness and colour temperature, if that's important. Find out how much current the bulb needs and make sure the power supply can provide at least that much current.
     
  11. JMW

    JMW

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    Jan 30, 2012
    If in fact it is 6 volts, why not try a "walwart". I'm certain you have one lying around that was too good to throw away.
     
  12. CocaCola

    CocaCola

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    Apr 7, 2012
    You will need a high capacity wall wart, unlike most of the cheap ones that are only a few 100mA... The 6.5 microscope bulbs I have seen are in the 18W range so at 6.5V they require almost 3 Amps... Not saying they don't exist, they certainly do but I suspect it's unlikely that someone would have one rated so high laying around...

    That is why I asked for more specific information on the bulb or microscope model number...
     
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