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Problem with Voltage Dividers

  1. Nov 17, 2012 #1
    i know this is a very basic question, but there's something i don't understand about voltage dividers.Vout is supposed to be(v2/V2+v1)* V, or the voltage drop across a resistor, but i don't see how this works in practice. When you put a load across the output, this changes the voltage drop of all the resistors in the circuit, so how is a voltage divider useful if you can't have a constant out value.
     
  2. jcsd
  3. Nov 18, 2012 #2
    It's "constant" within limits. Quiz-Question: For Vin=10V and a desired Vout=5V, how would you design the voltage divider if you want to stay within, say, 5% your nominal value when you connect a load of 1kΩ?
     
  4. Nov 18, 2012 #3
    Also, they are used when you need to give an input signal to a high impedance load. For example, if you have 5V and need a reference voltage of 3.3V to, say, an OP-AMP, you could use a voltage divider to get those 3.3V.
     
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