DC/AC generator

Discussion in 'The Projects Forum' started by Garry, Nov 7, 2011.

  1. Garry

    Thread Starter Member

    Jul 1, 2005
    12
    0
    Hi,

    I'm more of a digital/microcontroller guy, so I'm sort of out of my league here ...

    for some experiment, I'm looking for some circuit that will generate some sine(ish) A/C from D/C input, if possible with adjustable frequency (1-100Hz would be fine I guess), adjustable voltage (step-down only, 9-12V A/C would be enough with an input of up to 30V DC), and if possible a DC offset (e.g., 9V A/C +/- 9V D/C). Amps don't need to be very high, some 20-40mA should do nicely ...

    Adjustments via potentiometer would be OK, though it would be cool if the settings could be adjusted digitally (e.g. microcontroller etc.), allowing for some semi-automated tests.

    Any suggestions as to how to implement something like this?
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    Use a microcontroller with a DAC output.
     
  3. Garry

    Thread Starter Member

    Jul 1, 2005
    12
    0
    Which supports that load? Just looked at some spec docs, e.g. Atmel only has their DACs rated at up to 10mA ...
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You can use a power opamp in a non-inverting amplifier configuration.

    An L272 is an inexpensive and widely available power opamp that can source/sink up to 700mA.
     
  5. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    Thanks for this Wookie. If you need more drive, LM675 is good to 3A, though a bit more expensive.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Might check out the L165V, too - 3.5A, and under a buck if you look around for them.
    AvnetExpress sells them for $0.81 when you buy 1.
    Future Electronics has them for $0.79/ea
    Mouser & Digikey both have it for ~$1.71/ea.

    Cheapest I can find the LM675T is $3.12 @ Future Electronics. Mouser & Digikey are around $6.70 ea.
     
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