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ACS712 current sensor (20A)

ACS712 current sensor (20A)


  • Pay on-chip current sensor ACS712
  • The maximum measured current: 20A
  • The connection polarity is not important.
  • Power Supply: 5V power supply LED indication.
  • Interface: analog, the level of 185mV / A.
120 грн
Code: 222

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ACS712 current sensor is based on a principle discovered in 1879 by Edwin Hall (Edwin Hall), and named after him. Hall effect is the following: if the current-carrying conductor placed in a magnetic field is used, its edges EMF occurs directed perpendicular to both the current direction and to the direction of the magnetic field. The effect is illustrated in Fig. Through a thin plate of semiconductor material, called the Hall element, current flows I. In the presence of a magnetic field on a moving charge carriers (electrons) Lorentz force, bends the trajectory of the electrons, which leads to a redistribution of space charge in a Hall. Consequently, the edges of the plate parallel to the direction of current flow occurs EMF called the Hall voltage. This emf is proportional to the vector product of induction B on the current density I and has a typical value of the order of a few microvolts.

The sensitivity and output voltage ACS712

The output voltage of the sensor is proportional to the current flowing through the conduction path (from pins 1 and 2 to terminals 3 and 4). Available in three versions for different current sensor measuring ranges:

  • ± 5 A (ACS712-05B),   
  • ± 20 A (ACS712-20B),   
  • ± 30 A (ACS712-30A)

The corresponding levels of sensitivity of 185 mV / A, 100 mA / V and 66 mV / A. At zero current flowing through the sensor, the output voltage is equal to half the supply voltage (Vcc / 2). It should be noted that the output voltage at zero current and proportional sensitivity ACS712 supply voltage. This is particularly useful when used in conjunction with sensor ADC.

The accuracy of any ADC depends on the stability of the reference voltage. In most applications a microcontroller used as a reference voltage. Therefore, when an unstable power supply voltage measurements can not be accurate. However, if the reference voltage ADC make voltage sensor ACS712, the output voltage will compensate for any errors analog-to-digital conversion, due to the fluctuations of the reference voltage.

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