# Do i need a op amp?

Hi all

iam getting a voltage in range of -2.5v to +2.5v from the output of an voltage divider circuit.

and i want to add a +2.5v to the o/p to make it in range of 0 to 5v. do i need a op amp circuit for this?? if so how can i connect it??

I'm no expert, but I think and Op-Amp would work (Assuming it can input negative voltage).

I believe you would set it up as a comparator by wiring the non-inverting input to your -2.5 to +2.5 voltage range, and the inverting input to GND. Wire VCC to +5V, and GND to GND. Your output should switch to +5V when your non-inverting input is 2.5V, and GND when you non-inverting input is -2.5.

That's what I think, anyways :P.

I believe you would set it up as a comparator by wiring the non-inverting input to your -2.5 to +2.5 voltage range, and the inverting input to GND. Wire VCC to +5V, and GND to GND. Your output should switch to +5V when your non-inverting input is 2.5V, and GND when you non-inverting input is -2.5.

That would result is a digital output, with only a 0 or +5 output value.

i am getting a voltage in range of -2.5v to +2.5v from the output of an voltage divider circuit.

That would indicate a analog range of values and thus a comparitor circuit is not going to work, just need a op-amp circuit with a gain of 1 and an input offset of 2.5v.

Lefty

That would result is a digital output, with only a 0 or +5 output value.

Ah, sorry, I didn't read carefully enough to see that the OP needed the range, and not a digital output! :-[

can u give more clear about circuit connection? - Retrolefty

can u give more clear about circuit connection? - Retrolefty

The following link explain much better then I can. So while I can't draw you a specific circuit matching your requirements, I can show you a reference source.

http://masteringelectronicsdesign.com/how-to-derive-the-summing-amplifier-transfer-function/

Lefty