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ACHS-7124 Current Sensor Carrier -40A to +40A

Pololu item #: 4033
Brand: Pololu supply outlook
Status: Clearance 
RoHS 3 compliant

Price break Unit price (US$)
1 3.95 6.95

backorders allowed

Clearance notice: These older current sensors are on clearance at a discounted price and will be discontinued once remaining component stock is depleted.

This board is a simple carrier of Broadcom’s bidirectional ±40A ACHS-7124 Hall effect-based linear current sensor, which offers a low-resistance (~0.7 mΩ) current path and electrical isolation. This version accepts a bidirectional current input with a magnitude up to 40 A and outputs a proportional analog voltage (50 mV/A) centered at 2.5 V with a typical error of ±1.5%. It operates from 4.5 V to 5.5 V and is intended for use in 5 V systems.

Alternatives available with variations in these parameter(s): version Select variant…

 Description Specs (10) Pictures (8) Resources (5) FAQs (0) On the blog (1) 


This current sensor is a carrier board or breakout board for Broadcom’s ACHS-7121/7122/7123/7124/7125 Hall effect-based linear current sensors; we therefore recommend careful reading of the ACHS-7121/7122/7123 datasheet (1MB pdf) or ACHS-7124/7125 datasheet (1MB pdf) before using this product. The following list details some of the sensor’s key features:

  • The conductive path internal resistance is typically 0.7 mΩ, and the PCB is made with 2-oz copper, so very little power is lost in the board.
  • Use of a Hall effect sensor means the IC is able to electrically isolate the current path from the sensor’s electronics, which allows the sensor to be inserted anywhere along the current path and to be used in applications that require electrical isolation.
  • 80 kHz bandwidth that can optionally be decreased by adding a capacitor across the board pins marked “filter”.
  • High accuracy and reliability: typical total output error of ±1.5% at room temperature with factory calibration, an extremely stable output offset voltage, and almost zero magnetic hysteresis.
  • Robust sensor IC can tolerate 100 ms transient current spikes up to 100 A.
  • Wide operating temperature range of -40°C to 110°C.

The pads are labeled on the bottom silkscreen, as shown in the picture to the right. The silkscreen also shows the direction that is interpreted as positive current flow via the +i arrow.

We sell five different versions of this board (±10A, ±20A, ±30A, ±40A, and ±50A) so you should consider adding your own distinguishing marks or labels if you will be working simultaneously with multiple versions. A white box is provided on the bottom silkscreen of the board to make labeling easier. You can also distinguish the versions by reading the text on the IC.

Details for item #4033

ACHS-7124 Current Sensor Carrier -40A to +40A, top view.

ACHS-7124 Current Sensor Carrier -40A to +40A with included 0.1″ header pins.

The ACHS-7124 sensor operates at 5 V and is designed for bidirectional input current from -40 A to 40 A. When Vcc is 5 V, the output voltage is centered at 2.5 V and changes by 50 mV per amp of input current, with positive current increasing the output voltage and negative current decreasing the output voltage.

This board ships assembled with all surface mount components, and a 3×1 strip of 0.1″ header pins is included but not soldered in.

Using the sensor

This sensor has five required connections: the input current (IP+ and IP-), logic power (VCC and GND), and the sensor output (OUT).

The sensor requires a supply voltage of 4.5 V to 5.5 V to be connected across the VCC and GND pads, which are labeled on the bottom silkscreen, and the sensor outputs an analog voltage that is linearly proportional to the input current.

The FILTER pin lets you adjust the board’s bandwidth by adding a capacitor, CF, to ground (a ground pad has been added next to the FILTER pin for convenience) in parallel with the 1 nF capacitor that is already on the board. Without any external filter capacitor, the bandwidth is 80 kHz. The datasheet provides more information on how the external filter capacitor affects bandwidth.

You can insert the board into your current path in a variety of ways. For low-current applications, you can solder 0.1″ male header pins to the board via the smallest pair of through-holes on the input-current side of the board. For higher-current applications, you can solder wires directly to the through-holes that best match your wires, or you can use solderless ring terminal connectors. The largest pair of through-holes are big enough for #6 screws.

Current sensor carrier soldered with high-current wires.

Current sensor carrier with solderless ring terminal connectors (not included).

Warning: This product is intended for use below 30 V. Working with higher voltages can be extremely dangerous and should only be attempted by qualified individuals with appropriate equipment and protective gear.

Schematic and dimension diagrams

Schematic diagram of the ACHS-712x Current Sensor Carrier.

The dimension diagram is available as a downloadable PDF (318k pdf).

Comparison of the Pololu current sensor carriers

We have a variety of current sensors available with different ranges, sensitivities, and features. The table below summarizes our selection of active and preferred options:

ACS711 Current
Sensor Carriers

ACS71240 Current
Sensor Carriers

ACS724 Current
Sensor Carriers

ACS72981 Current
Sensor Carriers
Sensor IC: Allegro
Vcc range: 3 V–5.5 V 3.3V versions: 3.0 V–3.6 V
5V versions: 4.5 V–5.5 V
4.5 V–5.5 V 3.3V versions: 3.0 V–3.6 V
5V versions: 4.5 V–5.5 V
Current range /
±15.5 A / 90 mV/A
±31 A / 45 mV/A
Bidirectional 3.3V:
±10 A / 132 mV/A
±50 A / 26.4 mV/A

Unidirectional 5V:
0–⁠50 A / 80 mv/A

±2.5 A / 800 mV/A
±5 A / 400 mV/A
±10 A / 200 mV/A
±20 A / 100 mV/A
±30 A / 66 mV/A
±50 A / 40 mV/A

0–⁠5 A / 800 mv/A
0–⁠10 A / 400 mv/A
0–⁠20 A / 200 mv/A
0–⁠30 A / 133 mV/A

Bidirectional 3.3V:(1)
±50 A / 26.4 mV/A
±150 A / 8.8 mV/A

Unidirectional 3.3V:(1)
0–⁠50 A / 52.8 mv/A
0–⁠100 A / 26.4 mv/A

Bidirectional 5V:(2)
±50 A / 40 mV/A

Unidirectional 5V:(2)
0–⁠100 A / 40 mv/A
IC path resistance: 0.6 mΩ 0.6 mΩ 0.6 mΩ 0.2 mΩ
Max bandwidth: 100 kHz 120 kHz 120 kHz(3) 250 kHz
Size: 0.7″ × 0.8″ 0.7″ × 0.8″ 0.7″ × 0.8″ 0.7″ × 0.8″
Overcurrent fault output
Differential sensing
Non-ratiometric output
1-piece price: $3.49 $3.95 $6.95$7.49 $9.95
(1) Sensitivity when Vcc = 3.3 V; sensitivity is ratiometric.
(2) Sensitivity when Vcc = 5 V; sensitivity is ratiometric.
(3) Bandwidth can be reduced by adding a filter capacitor.

People often buy this product together with:

ACHS-7121 Current Sensor Carrier -10A to +10A ACHS-7121 Current Sensor Carrier -10A to +10A
ACHS-7122 Current Sensor Carrier -20A to +20A ACHS-7122 Current Sensor Carrier -20A to +20A
ACHS-7123 Current Sensor Carrier -30A to +30A ACHS-7123 Current Sensor Carrier -30A to +30A

Related Products

ACHS-7121 Current Sensor Carrier -10A to +10A
ACHS-7122 Current Sensor Carrier -20A to +20A
ACHS-7123 Current Sensor Carrier -30A to +30A
ACHS-7125 Current Sensor Carrier -50A to +50A
0.100" (2.54 mm) Breakaway Male Header: 1×40-Pin, Straight, Black
0.100" (2.54 mm) Breakaway Male Header: 1×40-Pin, Right Angle
0.100" (2.54 mm) Female Header: 1x3-Pin, Straight
0.1" (2.54mm) Crimp Connector Housing: 1x3-Pin 25-Pack
T Connector Male-Female Pair

Related Categories

ACHS-712x Current Sensor Carriers
Clearance Current Sensors
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Terminal Blocks
Premium Jumper Wires
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0.1″ (2.54 mm) Male Headers
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