# Vin

Discussion in 'General Electronics Discussion' started by n00b, Sep 16, 2014.

1. ### n00b

11
0
Sep 3, 2014
Hey, guys

The circuit below is a standard buffer amplifier. Vin can be any voltage between 1-10v but i would also like it to increase Vin by an additional 0.5v when an input between 1-10v is applied so that, for example; if a signal Vin is 1v, the signal that will actually be inputted is 1.5v all the way to a signal Vin of 10v which will be 10 + 0.5v = 10.5v.

thanks!

2. ### Harald KappModeratorModerator

12,458
2,986
Nov 17, 2011
Look at a difference amplifier (e.g. about half way down this page).
Vout=(V2-V1)*Rf/Ri
Set Rf=Ri for a gain of 1.
Set V2=Vin, V1=-0.5V, therefore V2-V1= Vin+0.5V

3. ### n00b

11
0
Sep 3, 2014
Sweet, thanks Harald!

4. ### n00b

11
0
Sep 3, 2014
Is there a simple way to keep Vin @ 0v if Vin<1v?

thanks~

5. ### Harald KappModeratorModerator

12,458
2,986
Nov 17, 2011
Do you mean keep Vout=0V for Vin <1V?

6. ### n00b

11
0
Sep 3, 2014
wops, that's what i meant.

7. ### Harald KappModeratorModerator

12,458
2,986
Nov 17, 2011
Have a look at this thread, it deals with a similar problem.