I am looking to manually adjust an output voltage to a get specific voltage. For example: the output voltage needs to be 2.5 VDC and my output may be 2.3 VDC or 2.8 VDC. I am looking for a way to manually adjust the voltage using a potentiometer (and possibly some op-amps). Any suggestions?
crutschow - the output is going to a microcontroller so the current requirements are in the mA range.
MrAl - the output will be constant, but for each circuit I make the voltage may be above or below what I want it to be (2.5VDC).
CCD - the classic LM317 voltage regulator can bring my voltage down to what I want, but if my starting voltage is too low I need to increase it somehow.
The output is coming from an accelerometer. The Accel is on a circuit board which is on a table. When the table is level, the Accel should output 2.5 VDC to the microcontroller. But circuit board doesn't sit level on the table, so I want to be able to adjust a Potentiometer to tell the microcontroller that the table is level.
The output is coming from an accelerometer. The Accel is on a circuit board which is on a table. When the table is level, the Accel should output 2.5 VDC to the microcontroller. But circuit board doesn't sit level on the table, so I want to be able to adjust a Potentiometer to tell the microcontroller that the table is level.
You're right. Alternatively, you could connect the ground of the ground leg of R2 to Vcc/2 (buffered by a voltage follower).
I think the key issue is which op-amp to use. You'll definitely want a rail-to-rail op-amp that can work with your supply voltage (likely 5V). Add the requirement that you want a through-hole component, and that narrows down the field quite a bit. I'd check out what National has to offer (like the LM6142) as well as Microchip.