I would like to transform a 0-10V into a 0-5V so I can read it with "5V MCU" (like the AVR/Arduinos).
In the most basic case I would just put 2 resistors and do a divider, but since I don't know how that would affect the signal source I figure that I could add a buffer with op-amps since it would be safer.
So I could add a voltage follower on both sides of the divider.
simulate this circuit – Schematic created using CircuitLab
Or I could do a amplifier with amplification with 0.5 and then a voltage follower as a buffer.
Is it overkill to add the op-amps? Is it a good idea to do this kind of things, or is there another way?
Best Answer
Your first circuit is fine. You could even use 100k resistors instead of 10k to save power. Note that your first op amp will need to output 0-10V, which means you won't be able to run it off of a 0-10V supply. If you don't have a rail-to-rail op amp, I'd recommend at least a +13/-3 V supply.
As Matt said, your second circuit will not work. The gain of a non-inverting amplifier cannot be less than 1. You could use a pair of inverting amplifiers, with the first one having a gain of 0.5. That would help with your output range as well, but there would be a small load on your source.