current amplifier

Discussion in 'Homework Help' started by balaji selva, Nov 29, 2013.

  1. balaji selva

    Thread Starter New Member

    Nov 29, 2013
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    can u suggest some current amplifiers for me ah...i have to amplify 0-20mA to 0-120mA....
     
  2. WBahn

    Moderator

    Mar 31, 2012
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    Need some better specs than that.

    What kind of voltages are needed (what is the impedance of the intended load)?

    How fast does the current need to be able to change.
     
  3. balaji selva

    Thread Starter New Member

    Nov 29, 2013
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    200mA to a 500 ohm device at the o/p side.....
    fastness of current change does not matter................
    o/p open circuit voltage of 100V
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Something like this perhaps?
     
  5. balaji selva

    Thread Starter New Member

    Nov 29, 2013
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    what's M1 in this circuit...what type of mosfet
     
  6. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,794
    1,103
    N-channel, with a voltage rating >100V and a low Rds(on), e.g. IRFP4668.
    N.B the FET and load will have to dissipate up to 5W and 20W respectively, so both will need substantial heatsinks.
    If the load has any inductive component a reverse-biased diode across it will be needed to protect the FET from voltage spikes.
     
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