Voltage divider before the input of an LM324N used as a comparator

[nanawhite107]

I am designing a driving system to control some servomotors, and since my microcontroller can not drive enough current, I had thought in do this with some LM324 as comparators.

Here is the lm324n datesheet.

The thing is that I have a fixed 5 VDC source, and I want the negative input of the opamp being 1V. This way I can source the LM324 with 5 VDC being sure it will not switch.

I have two questions:

1. It is correct if I just put a voltage divider between my DC Source and the input of LM324N?

2. Since the input impedance of LM324N is very high, I was thinking of using only one voltage divider instead of one for each input, is this correct?

EDIT: As you can see in the schematic, my idea was to drive the servomotor with the lm324. Output current of this operational amplifier is about 20mA acording datasheet. My servomotor is the famous sg90 towerpro, there is a lot of missunderstanding about how many current does it draw. As @Peter Bennet commented, I thought lm324n does not source too much current, so I did an experiment and it worked fine. So I thought it would be enough.

[RobertoBozzolo]

Hello, what has to do this question with National Instruments material at all?

I see that you have already posted some question to the Motion Control board: it is probably a better board where to post similar questions than the LabWindows/CVI one, but again: are you planning to integrate in this project any NI item? If not, then there are probably better sites where to find some help, notably the motor producer's one.