Voltage sensor

reks

i need to sense voltage across a batteyr. it will be limited between 32V and 42V. i need a circuit which will sense this voltage across the battery(a differential amp ckt kinda thing) and then scale it to 0 to 10V so as to give to FPGA.
so do i need two opamp stages? 1 with diffeential opamp mode , and then a scaling or amplifying stage?
the differential mode to sense the battery across the two terminals of the battery is a must, i cant make out how to accomplish.Pleaase help me.

Spiral_72

Do you plan to use one of the Basic Stamps for this, or purely components?

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"puff"...... Smile, there went another one.

Mike Green

1) This is a forum for discussion of Parallax sensors or maybe the use of other sensors with Parallax microcontrollers. The "Sandbox" forum here is for discussion of other topics.

2) Most differential amplifiers still have a limit on the maximum voltage relative to ground that they can handle without damage and 32-42V is on the high range. A simple passive voltage divider (1:4 or 1:5) could reduce this to a more reasonable range (like 6-8V), then one op-amp stage could remove the bias (6V) and a second stage could provide fixed amplification to bring it back to a 0-10V range. You'd probably need a regulated +12V supply for the op-amps.