Before I begin with my question just so you know I'm not very familiar with electrical engineering so please forgive if I ask some dumb question :)

What I want is to know if I can use Hall Effect sensor (ACS712 for example) to measure DC current pulled from LOAD device.

To be more precise, I want to have my measuring device connected on the same DC source as the LOAD device.

However, I noticed on this module on the left for example that I can put it on the "VCC" wire for example, and "OUT" on the right to my PIC microcontroller and to read voltage there, but can I connect my "measuring device" and "VCC" and "GND" of this sensor as well on the same source in series before the load device, would that current detection be affected with "measuring device" it self?

If the answer is yes, can you please post a scheme how this needs to be wired please.

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  • \$\begingroup\$ What does the data sheet tell you and if you haven't read it I suggest you make a start. \$\endgroup\$
    – Andy aka
    Apr 26, 2016 at 10:30
  • \$\begingroup\$ What you must consider is: what is the reference for the measurement? If the sensor measures currents passed through its own supply voltage, it will not notice for example when the supply voltage and current are both reduced at once, because then the reference also gets reduced accordingly. So you need a reliable source of supply. Ideally, a separate voltage reference. \$\endgroup\$
    – Lundin
    Apr 26, 2016 at 11:07

1 Answer 1


The device measures the current flowing between the screw terminals, which are isolated from everything else. the pins are to power the hall effect sensor only, however, there's no reason you couldn't have power going through the screw terminals and then going to anything you want, those screw terminals are isolated from the pins so measuring itself is fine. Although those hall sensors aren't known for having amazingly good sensitivity, if you've got a 5A sensor, you'd be hard pressed to measure with an accuracy (or resolution) of much better than 50mA.

  • \$\begingroup\$ So if I want to measure drop of 2-5mA for example? \$\endgroup\$
    – ShP
    Apr 26, 2016 at 10:40
  • \$\begingroup\$ BTW, not sure if you understand my question, maybe I didn't explain good enough, I know that part for current between the screw terminals, but I was wondering if I can use the same power source to bring power on pins to power sensor as well instead of having separate power source for that. \$\endgroup\$
    – ShP
    Apr 26, 2016 at 10:43
  • \$\begingroup\$ As long as it's the right voltage, sure no problem, that's the nice thing about isolated sensors, you can connect them to just about anything, they can measure themselves no problem. \$\endgroup\$
    – Sam
    Apr 26, 2016 at 10:48
  • \$\begingroup\$ Ok thanks! It's more clear now. Hopefully I want mess up everything :) \$\endgroup\$
    – ShP
    Apr 26, 2016 at 10:59
  • \$\begingroup\$ Don't worry, those sensors are pretty robust \$\endgroup\$
    – Sam
    Apr 26, 2016 at 11:03

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