choosing High Wattage Resistor...

Discussion in 'General Electronics Chat' started by Avicreats, Mar 30, 2013.

  1. Avicreats

    Thread Starter New Member

    Jan 18, 2013
    19
    0
    I have to convert (0 to 2A)current rom Current Transformer into voltage using an op amp and get an output voltage rating of (0 to 5V). Can I use a 2.7ohm resistor? I have attached the circuit. If my calculations are right, then the wattage of the resistor during maximum current flow i.e 2Amps is, P=I*I*R = 2*2*2.7 =10.8Watts.
    Is this the right way of calculating the resistor? If so I am sure there will be no resistor for such a wattage rating.
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    Increase the gain of the op amp circuit by 10 and you can reduce the resistor by a 10.
    Increase the gain of the op amp circuit by 100 and you can reduce the resistor by a factor of 100.
     
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