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Can lm358 0pamp amplifies 0-0.1 v to 0 to 5 volt?how?+what is - VCC ?

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nikhiljoshi

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Dear Sir,

The project is to establish the current sensor which measures current up to 0-5 amp(DC). I have used 0.1 ohm(5 watt) value resistor for sampling the current and I got 0 to 0.5 volt according to 0-5amp.but the problem is that our ADC inputs are not compatible for that much of lower input voltage.it needs the range from 0-5 volt.so its necessary that amplify the 0-0.5 volt to 0-5 volt which we directly fed to ADC analog channel and give the perfect output with respect to 0-5amp.so I need to be design the voltage amplifier circuit using an OP-EMP with appropriate gain.
1) Is it possible with LM358 ?
2) how can we give the negative Vcc to OP-AMP ?
3) Can we GROUND the -Vcc terminal instead of it?
4) sir what is the time-limit up to that i can continuously measure the current of 5 amp with 0.1 ohm(5 watt) value resistor?
 

Can we GROUND the -Vcc terminal instead of it?
Does this refer to LM358?
LM358 can work fine with a single supply , actually the pinout has a V+ and gnd so you can just connect the positive and ground to supply th opamp.

The power consumption on a resistor can be found from P=V*I => P=I² *R
In your case , 5² * 0.1 = 25 * 0.1 = 2.5W so you have no problem at all with the resistor.

To amplify the voltage you get from the shunt resistor you can use a differential amplifier

DiffAmp.jpg

Connect V1 to the ground side of the shunt resistor and v2 to the positive side , Vr can be connected to ground.
Select the resistors to get the gain you need, for example with R1=1K and Rf=5K the gain is 5x

Alex
 

Thank u for reply sir..

---------- Post added at 03:40 ---------- Previous post was at 03:08 ----------

the resistor ratting are good still it is highly heated in within 5 minutes....

so what is the time-limit up to that i can continuously measure the current of 5 amp with 0.1 ohm(5 watt) value resistor?
 

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