It means that input signals can be in the range of 0.5 volts below ground to 0.5 volts above Vcc. This suggests clamping diodes on the input terminals which can dissipate some current but not a great deal as the diodes are probably "small" in terms of die area.

It would be handy to know what limits there are on the supply pins. Fragments of a datasheet can cause one to jump to unsubstantiated conclusions.

Well it will have single supply with 3.3V on V+ (and ground to V-). I suppose i can use a voltage divider (with 2 resistors) before the input terminals so that i am within the limits of the input signlas range?

 

Well it will have single supply with 3.3V on V+ (and ground to V-). I suppose i can use a voltage divider (with 2 resistors) before the input terminals so that i am within the limits of the input signlas range?

I don't know why you think you need a voltage divider 0 and 3.3 Volts are between -0.5v and 3.8V. Are they not?

 

Is this a school assignment or a personal project?

 

I don't know why you think you need a voltage divider 0 and 3.3 Volts are between -0.5v and 3.8V. Are they not?

My supply will be ground (0) to V- and 3.3V to V+.So the range i can measure is -0.5-3.8 yes. But my measurements (Vin+ and Vin-) may reach 12V or 5V that's why i consider using 2(at bothVin+ and Vin-) resistors as voltage divider.

 

Is this a school assignment or a personal project?

School assignement.

 

Very often you can get away with a single op amp differential amplifier as shown previously in this thread. It takes one op amp section and four resistors and you can set the gain too.
When you need very precise operation then you turn to an instrumentation op amp. You can construct one with three op amp sections and some resistors or you can buy one already made.
In any case the choice depends on what specifications you need to make the measurements. You can look up the various specs of op amps and instrumentation op amps and compare to see how this affects your measurements.

Sometimes you have to throw in a little filtering action too and then you might add some other components too like small capacitors. The speed of response is also another specification though and capacitors may slow down the op amp a little so an overall circuit analysis is always a good idea once you decide on a certain topology.

 

Hello,

I would like to construct a circuit that measures the differential voltage on the load of the circuit depicted below I think about something with an op-amp.

I think your confused

#1 measuring the drop across terminals doesn't require a whole digram of a whole circuit unless you are "trying to minimize cost of measuring voltage"

#2 lighting up a strip of LEDS based on voltage isn't measuring voltage. "it works, kinda, kinda hardly"

#3 that's because measuring voltage is the MOST difficult thing you can do, perdiod, with electronics

#4 ALL YOU NEED IS A SHUNT RESISTOR AND A VOLTAGE METER. you will likely dial it in rather than do a hot mess of calculations. though you should use the shunt equations to insure you don't blast off your analog meter.

#5 you need a list of common components that are (a) current sensitive (b) voltage sensitive. that will tell you what you can put across the terminal to make a TRIVIAL voltage deflector

YOUR PROPOSAL IS RIDICULOUS - adding a small simple thing to measure true voltage. Can't be done. It can only be remediated with 1/2 truths using a small circuit.

Then when you dig down to solving the problem for real, you have a costly FLUKE in your hand.

 

slackguy.

It's a: School assignment.

So he has to follow the assignment.

E