I want use LM324 to measure a voltage signal,all input range is 200mv,and my step resolution is 1mV,but LM324 have a 2mv typical offset voltage,And how can I to cancer so large offset voltage?
my circuit require low cost,so I can't use other advanced amp.
Another reason is my company have much storing lm324,So we need to use this chip.
How to cancer offset voltage?
and how to do with a great deal product's produce?
Add or subtract a small voltage to/from the inactive input of the opamp.For instance,if your circuit is inverting,instead of grounding the positive input,connect it to a voltage divider that can be changed from -2 to +2 mV.Then adjust the divider till the output offset is 0.
Hi,mag,
You can adjust the output of the last opamp to be zero by changing the input offset of the first one.After all they are DC coupled,right?
So it won't be a problem,trust me.
Watching the circuit from the input, the second stage offset is affected by the first stage gain (the higher 1st stage gain, the lower 2nd stage offset contribution)
Besides compensating the offset you must check the drift (offset vs temperature) what usually is a bit harder to deal with.