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Unread 24-12-2005, 07:30
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Al Skierkiewicz Al Skierkiewicz is offline
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Re: Circuit design help - power supply - Non FIRST

Josh,
You can tell a lot about the function generator you linked to by looking at the power, the circuit design (quad opamp) and the picture. A single ended power supply on this opamp will render the output DC shifted to half the voltage of the power supply, in this case a 9 volt battery. Without a big capacitor on the output to block the DC (I can't see a big cap in the picture) the output will generate waveforms that center on half the power supply more or less so expect the output to be around +4 volts most of the time. In this application you are not really concerned about efficiency in the amplifier should you use one. What you are asking can be accomplished with a switching circuit in series with a variable DC power supply or a power amp where you can adjust the offset voltage of the output to be at some DC potential. With a power amp, the efficiency goes way down in this arrangement as the amplifier stage is drawing current all the time whether there is signal or not.
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Al
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Storming the Tower since 1996.