Does an amplifier have a max gain ?

Discussion in 'The Projects Forum' started by simeonz11, Jan 8, 2010.

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  1. simeonz11

    Thread Starter Active Member

    Apr 29, 2008
    For this current project of mine , I need to amplify an ac sine wave +-0.5v(1vp-p) . It is a pure sine wave by all means and perfectly symetric + and - etc ... I wont be dealing with anything but a pure sine in the audio range .

    I wish to amplify this to a maximum of +-24 volts . The opa604 .

    Now I have located an op amp that seems to suit my needs , my question is the following .

    Can a 50 or 100x gain of such a small signal be amplified precisely at +-24 volts with a single op amp , or do I need 2 x op amps .

    Does open loop gain mean max gain of an amplifier , all datasheets have a max open loop gain and a minimum gain , but there is no talk of maximum gain in closed loop .

    Also , if this op amp is specified for +-24 volts , will it do harm if I use 2 x brand new 12v batteries , I know these can reach 13.8 volts when new , so +- 27.6

    thx .
    Last edited: Jan 8, 2010
  2. beenthere

    Retired Moderator

    Apr 20, 2004
  3. SgtWookie


    Jul 17, 2007
    OK, wait a minute...

    Do you mean one battery for a Vcc of 13v and another for a Vee of -13v giving a total 26v?
    Or do you mean you're using four batteries; two for a Vcc of +26v and two for a Vee of -26v?

    And what kind of output current are you expecting to get out of this amplifier?
  4. t06afre

    AAC Fanatic!

    May 11, 2009
    You will most most probably damage your your circuit if the power rails exceed 25 volt. From the data sheet we can also read that then the power supply is +/-15 volt the highest output voltage will be somewhere between 11 and 12 volt (+/-) with a 600 ohm load. If you use a +/- 24 volt power supply the output voltage will be around 20 volt maximum. But this will depend somewhat on the load. Anyway you will never get +/- 24 volt output swing with this circuit.
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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