I really need help learning to use op-amps. I am a knowledgeable individual in regards to Arduino and basic circuits, but I still struggle in some of the more advanced electrical engineering things, such as op amps. Adafruit sells an op-amp here (http://www.adafruit.com/products/808), that they have a nice tutorial for, and that I am definitely going to buy. However, I want to become capable of using non-rail to rail op amps too, so I thought I’d grab some from other sources to play with too, for my learning.
Why do I need an op amp?
-My goal is to measure current, using very low resistance resistors from DigiKey. ex: 0.001 Ohm to 0.01 Ohm.
I want to have several different setups, that range from 10A DC to 100A DC, as well as wall current up to 1A AC and 10A AC.
-that’s where the op amp comes in—to amplify the voltage drop across the resistor so that it has a range of 0-5V for the ADC on the arduino.
I am looking at the following online, and have downloaded the datasheets for many of them (see attached files):
TL072 - http://www.ti.com/lit/ds/symlink/tl072.pdf
NE5532 - http://www.taydaelectronics.com/datasheets/A-031.pdf
What parameters should I look for? How do I hook one up? (can they all be used as this shows? - http://www.adafruit.com/blog/2011/11/02/almost-all-opamp-circuits-you-will-ever-need-with-formulas/)
Additionally, some (such as the NE5532, datasheet link above) specify the input should be +/-5V to +/- 15V (operating conditions), and some only specify Absolute Maximums. Does the Arduino (0V ground and +5V Vcc) meet this condition, or would it have to be -5 to +5 to meet the operating condition of +/-5V minimum?
How do I know what the max gain is that I can use, or what max resistors I should use?
Are these biased? What is a bias and how to I account for it? It seems they are not rail to rail, but I’m not sure what that means.
Thanks for any help you can give!
TL071 datasheet.pdf (281 KB)
TL072 datasheet.pdf (1.7 MB)
TL084 datasheet.pdf (312 KB)