Op-amp tutorial for total dummies?

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Axe_Murderer

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I have the need to measure 0-24V with a PIC. Needless to say the PIC isn't going to like 24V much. I could use a voltage divider but I don't want to loose too much accuracy in the process (although maybe it won't be that bad?). Regardless this seems like a good opportunity to learn how to use op amps. I did a quick Google and... YIKES!

Does anybody have a link for a good op-amp tutorial for total newbies? Should I skip it and just use a potential divider?

Thanks.
 
If you just want to scale 0 to 24 volts down to 0 to 5 volts for the input to your pic, just use a potential divider.
I dont see any advantage in using an opamp.
If you are worried about loss of accuracy with the resistors in the potential divider, you will have exactly the same problem with the opamp. The gain of the opamp is set using resistors.
So, just get some decent resistors and make a potential divider I think.

JimB
 
I agree with JimB, but if you want to learn about op amps, look up National Semiconductor's Application note: AN-20. There are others like AN-29 and AN-31, but begin with AN-20.
 

As already suggested, you only need a potential divider, an opamp wouldn't change anything - EXCEPT allow you to have a higher input impedance. You might like to check my analogue PIC tutorial?.

The accuracy won't be any different, a potential divider (assuming it's accurate?) doesn't reduce accuracy - bear in mind, this is how you multi-meter and scope both work!.
 
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