# Shifting 0-5V signal to -2.5-2.5V

1. Jul 16, 2010

### bassplayer142

Shifting 0--5V signal to -2.5--2.5V

I have a DAC coming from my micro with a signal that will vary anywhere from 0-5Volts. What are my options of shifting that down so I can get a -2.5 -- 2.5V swing? Thanks!

2. Jul 16, 2010

### waht

Re: Shifting 0--5V signal to -2.5--2.5V

In a op-amp voltage difference amplifier, you could subtract 2.5V from the input:

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3. Jul 16, 2010

### bassplayer142

Re: Shifting 0--5V signal to -2.5--2.5V

For this setup I will need to supply a positive voltage on pin 7 and a negative one on pin 4 right? thanks

4. Jul 16, 2010

### uart

Re: Shifting 0--5V signal to -2.5--2.5V

Yes, about +5 / -5 volts DC at a minimum.

There may be a much simpler solution but without a more detailed description of the nature of the signal then you mightn't get it.

Last edited: Jul 16, 2010
5. Jul 16, 2010

Re: Shifting 0--5V signal to -2.5--2.5V

Yes, you need a bipolar power supply. Your circuit is a unipolar to bipolar converter. If interested, I have an article about this type of circuit here:

Design a Unipolar to Bipolar Converter for a Unipolar Voltage Output DAC
http://masteringelectronicsdesign.com/design-a-unipolar-to-bipolar-converter-for-a-unipolar-voltage-output-dac/" [Broken]

Last edited by a moderator: May 4, 2017
6. Jul 16, 2010

### schip666!

Re: Shifting 0--5V signal to -2.5--2.5V

From your name, bassplayer, I'm thinking that you have an audio signal?

If it is over 10Hz or so, presuming that the destination is biased around 0v, you might be able to just put a big capacitor in the signal line. You might also get away with using a resistor divider to a negative supply voltage without bothering with an Op-Amp.

7. Jul 18, 2010

### bassplayer142

Re: Shifting 0--5V signal to -2.5--2.5V

Actually I'm working on a laser scanner system for light show with some mirror galvanometers. I don't have a datasheet on them or any type of function generator so having an easily adjustable supply will be great for finding the limits of operation. Thanks for all the posts, its been a great help!

8. Jul 18, 2010

### schip666!

Re: Shifting 0--5V signal to -2.5--2.5V

Then they are pretty much just speaker voice coils, and a inline capacitor will do the trick. However you probably need more power than the PC output can push. Perhaps more than the PC headphone output too, but you could try that or a small powered speaker system for a start.