okay so here's the thing. In my opinion and experience with current sensing using a sense resistor and a built diff. amp using in your case the LM317 or in my case the LM324 or LM358 op amps, the voltage drop is far to small across the sense resistor.
What you can do is one of the following:
1. Configure the op-amps in an Instrumentation amplifier configuration.
2. Buy an Instrumentation amplifer eg. AD620 - beautiful IC which works extremely well and very accurately!
3. Buy a breakout board from sparkfun : ACS712 beautiful board requiring no sense resistor.
4. Use a sense amplifier such as the MAX4173 across the sense resistor.
I just finished building a power meter which required current sensing, with the same spec as you. All of the above techniques worked for me, however I chose to go with number 2 in my design.
Hope this helps;
Gooduck
1.
https://www.google.co.za/search?q=instrumentation+amplifier+design&aq=3&oq=instrumentation+amplifier&sugexp=chrome,mod=7&sourceid=chrome&ie=UTF-8&safe=active
2.
https://www.sparkfun.com/products/8882
3.**broken link removed**
4. **broken link removed**
Please let me know if this helps.
- - - Updated - - -
okay so here's the thing. In my opinion and experience with current sensing using a sense resistor and a built diff. amp using in your case the LM317 or in my case the LM324 or LM358 op amps, the voltage drop is far to small across the sense resistor.
What you can do is one of the following:
1. Configure the op-amps in an Instrumentation amplifier configuration.
2. Buy an Instrumentation amplifer eg. AD620 - beautiful IC which works extremely well and very accurately!
3. Buy a breakout board from sparkfun : ACS712 beautiful board requiring no sense resistor.
4. Use a sense amplifier such as the MAX4173 across the sense resistor.
I just finished building a power meter which required current sensing, with the same spec as you. All of the above techniques worked for me, however I chose to go with number 2 in my design.
Hope this helps;
Gooduck
1.
https://www.google.co.za/search?q=instrumentation+amplifier+design&aq=3&oq=instrumentation+amplifier&sugexp=chrome,mod=7&sourceid=chrome&ie=UTF-8&safe=active
2.
https://www.sparkfun.com/products/8882
3.**broken link removed**
4. **broken link removed**
Please let me know if this helps.