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First off I'm sorry for such a dumb question, but I couldn't find any of my analog circuit books. Basically all I need is a circuit that will act as a high impedance buffer and variably offset the output signal to +1-+6V. I want to pass to actively DC bias an audio signal.
Could I just run the signal into a 1K resistor and then into the non inverting input of my op-amp? Then run a 100k resistor from that same input to a variable 1-6v DC power supply?
Registered Member #1667
Joined: Sat Aug 30 2008, 09:57PM
Location:
Posts: 374
what output impedance do you need? If high impedance is ok, a simple x2 non-inverting amplifier and two resistors with equal ratings connected as an analogue adder will do (the other input would need 2..12V for it to work within your specs.
Another option would be to use a unity gain buffer, add 1-6V and feed the output into a x2 non-inverting buffer.
I'm just using it to feed an audio signal into a PWM chip. When I put the audio signal un-modified it kills the square wave output. When I DC couple the signal I get modulation. I'd just like to remove the distortion from the capacitor.
Registered Member #3610
Joined: Thu Jan 13 2011, 03:29AM
Location: Seattle, WA
Posts: 506
Have you tried using a resistor divider between Vcc and Gnd after the capacitor to bias the signal? I don't know what circuit you're using, but it sounds like the portions of the audio signal are out of the usable range and causing the PWM IC to cut off entirely.
If you want to use an op amp, this is a handy reference.
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stupidely easy op amp question
