resistor or op-amp for output attenuation?

Discussion in 'The Projects Forum' started by Neil Groves, Dec 2, 2011.

  1. Neil Groves

    Thread Starter Member

    Sep 14, 2011
    125
    3
    I just started using my home built function generator and discovered the outputs are way too large for what i need, funny when i built it i thought only 3v sinewave.....thats no good, well as it turns out i need 10mv-100mv output to test amps and filter circuits lol

    So my question is can i use a simple resistor ladder network as my attenuator or is it better to use an op amp on the output stage so i can make the output variable?

    i don't know how to use an op amp as an attenuator though, maybe someone can advise?

    I'm not an engineer, just a lowely backroom hobbyist so go easy on me :)

    Neil.
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,452
    3,371
    Use two resistors in a voltage divider circuit.
     
  3. Neil Groves

    Thread Starter Member

    Sep 14, 2011
    125
    3
    ok thanks Mr Chips.

    Neil.
     
  4. MrChips

    Moderator

    Oct 2, 2009
    12,452
    3,371
    Do you need a schematic diagram?
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You can use a pot as a variable attenuator.

    Connect the output of the signal generator to one end of the pot.
    Connect ground to the other end of the pot.
    Take the output from the wiper of the pot (most often the middle terminal).

    The signal will be fairly high impedance. You can use an opamp wired as a voltage follower/buffer to make it a low impedance output.
     
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