Op. amp tuned to dynamic range ?

[pilotcj525]

Op. amp tuned to "dynamic range"?

You'll have to excuse me if this is a silly question, but I'm self taught in electrical engineering practices, and there are some simple things I've missed.

Here is what I am trying to do(hypothetically):

I have a sensor/ transducer that has a ratiometric output from approx 0-5V. However, the sensor will never be in a situation where the quantity it is observing drops to a point where a <3V output would be required. In other words, the output will never drop below 3V

No. I want to take that dynamic range(is this the right phrase) of 3-5V and scale it to 0-3.3V for ADC. This way I can get the maximum resolution for the operational output of the sensor. Of course there will be both hardware and software filtering of this amplified signal..

but my question is, how would I scale a 3-5V signal to 0-3.3V?

-CJ

 

[Hammie]

You could use a 3 volt zener diode. It will not begin to conduct until the input reaches 3 volts.

 

[berkeman]

Welcome to PF, Pilot. The best way to offset and scale your sensor input is with an opamp circuit. That will give you accurate offset and scale factors, and it won't vary with temperature or other factors. I'd like to recommend that you pick up a copy of the book "The Art of Electronics" by Horowitz and Hill. You can get it from Amazon.com, or most school/technical bookstores. It's a great beginning electronics book, and I'm betting that you will really enjoy reading it. The opamp chapter will give you all that you need to design the offset and scaling circuit. Have fun!

 

[chroot]

Even the info on hyperphysics might help:

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/opampvar.html

Look at the "amplified difference amp" configuration.

- Warren