My input to Arduino is 3A. How should i measure the current.
If possible can you give me methods like hall effect sensor ( but since it takes time to reach home)
searching for another method?
And arduino analog pin current rating is 40 mA and my input current is 3A......
Thanks in advance
- Do you understand what current is?
- Have you Googled your question?
- You may need a new keyboard, your shift key seems to be stuck.
Pieter
vijay_1996:
And arduino analog pin current rating is 40 mA
Not when used as an analog input.
An Arduino can't measure current on it's own, you need to interface it with a current sensor such as an INA219 module.
Also on Youtube.
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If you supply the correct input voltage then the Arduino (or whatever) will consume the correct amount of current. It doesn't matter if you have a 3A power supply or a 300A supply, the voltage is what determines how much current flows.
Most power supply problems are from too-little current. A 3A power supply with a motor that requires 6A starting current will be a problem.
Your question is phrased very unclear. You may have misunderstood something.
I suspect that you have a 3A power supply, and you are wondering if this is too much for your arduino?
In is case, you need to learn about Voltage, measured in Volts (V); and about Current, measured in Ampere (A). Go to wikipedia and/ or google.
In short: your power supply needs to be the correct voltage. Read the technical specs for your arduino to find out the correct voltage.
Regarding the current:
the current depends on what kind of loads in addition to your arduino are connected. The arduino itself uses only a few mA. the maximum of 40mA per Output pin is only reached, if you actually connect loads to these pins, which draw this amount of current.
The power supply will only supply as much current, as the circuit demands. So if the circuit pulls e.g. 1A, then even a 3A power supply delivers only 1A.
The current rating on the power supply is always a MAXIMUM rating, not an actual current.
A problem arises, if your circuit demands more current than then PS can deliver. E.g. if your circuit needs 4A, but your power supply can only deliver max. 3A. Your PS will overheat and/or shut down. Then you need a stronger power supply.
You can measure the current of your circuit with a digital multimeter.
In case you actually mean what you wrote - to measure a current of up to 3A WITH THE HELP of your arduino:
If this is a DC low voltage current, you can use a low ohm measuring resistor, and measure the voltage across the resistor with an AD analog input.
If this is a mains AC current, look into current transformers.
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thanks so much hydro
Actually we can measure current using arduino by converting it into voltage
See about ACS 712 it is an hall effect current sensor where it converts the current into voltage its resolution is 185mV/A. And there are many ratings by using that we can give or keep the sensor and convert it to voltage and can measure after having some calibration.
But my problem is it takes lot of time for the product to reach me so I thought to ask so that I could find some different solution.
My project is actually based on MPPT ( MAXIMUM POWER POINT TRACKING) so I need the inputs as current and voltage and so I need some current sensor because my inputs to change the duty cycle are the "i" and "v".
Thanks bro.. and have a nice day.. 
vijay_1996:
My project is actually based on MPPT ( MAXIMUM POWER POINT TRACKING) so I need the inputs as current and voltage and so I need some current sensor because my inputs to change the duty cycle are the "i" and "v".
Then your title is very misleading. It should say "HOW TO MEASURE CURRENT WITH AN ARDUINO ?
I know it is only a 1 word difference - but the difference in meaning is HUGE. You would not say you are "going for a walk in my dog". But if you did everyone would know you had made a mistake. However the concept of measuring current in an Arduino is not obviously a mistake.
...R
PS. If you edit your Original Post you can correct the title.
Pieter, which thing you are talking about and keyboard works pretty fine..
And there are solutions to measure current in arduino i already know some modules which convert current to voltage like ACS 712 and INS219 module which JIGGY NINJA was talking about and my problem is the module takes time to reach my home so I thought it would help me if there was another solution and I my question is how to measure current and I know to use a multimeter and all the kind of things to use it .....
Robin2:
Then your title is very misleading. It should say "HOW TO MEASURE CURRENT WITH AN ARDUINO ?I know it is only a 1 word difference - but the difference in meaning is HUGE. You would not say you are "going for a walk in my dog". But if you did everyone would know you had made a mistake. However the concept of measuring current in an Arduino is not obviously a mistake.
...R
PS. If you edit your Original Post you can correct the title.
Thanks bro for correcting i ll change
There is no native way in any of the Arduinos to measure current. The only way to really measure current well is to measure voltage across a small-value sense resistor. An Arduino Uno has no capabilities on-board to be good for this. An Arduino Mega, and certain other AVR devices can use differential inputs to the ADC with a programmable gain amplifier (such as x20), but this has limited use because of input restrictions. The voltages applied to any input must be between VCC and GND. This would mean that either the Arduino's power supply must be isolated from the current you are measuring (like with a battery or transformer), or the power supply you are measuring cannot exceed the value of the chip's VCC. The Arm based boards might have differential input ADCs as well, but they will probably have the same input restriction as the Mega and unhelpful as well.
An external device like the INA219 is best for this. It is specifically designed for power measurement after all, and has a built in ADC so you can pull that data over an I2C connection. A proper current sensing chip will also have a wider range of input voltages that can be used. The INA219 can be powered from 3V - 5.5V, and can measure current sensors connected to up to a 26V bus without needing to be isolated from it.
As a bonus feature, it can also measure the voltage and has a hardware multiplier to automatically calculate power. Pretty much everything is offloaded to the chip, you just need to set it up properly.
I assume this is for some kind of solar project, am I right? I imagine it'll probably be producing more than 5V at it's best, so a chip that's properly designed for current sensing will be much easier to get to work than some random homebrew solution you hack together from Internet advice.
If you need something with different specs (particularly if you need to measure more than 26V), you can browse around a place like Texas Instruments to see what else exists. TI makes much more than just overpriced graphing calculators. If you can't find what you like at TI, you can also check other manufacterers like Analog Devices, Maxim, NXP/Nexperia, or Microchip and hunt around there.