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Description: This current sensor gives precise current measurement for both AC and DC signals. These are good sensors for metering and measuring overall power consumption of systems. The ACS712 current sensor measures up to 5A of DC or AC current. We added an opamp gain stage for more sensitive current measurements. By adjusting the gain (from 4.27 to 47) you can measure very small currents.
The ACS712 Low Current Sensor Breakout outputs an analog voltage that varies linearly with sensed current. To calibrate, first set the output offset to the desired level (with zero current on the sense lines, read output with a DVM). Then with a known current input (a 100mA limited supply works well for this), set the output deflection with the gain pot. Sensitivity is then calculated as (Vref - Vdeflect)/(current input).
The bandwidth on the ACS712 Low Current Sensor Breakout has been set to 34Hz to reduce noise when using at high gains. The full 80KHz bandwidth that the sensor is capable of can be recovered by removing C1. See schematic for more details.
Based on 1 ratings:
Have spent a few hours with this, looked over the wiring many times, read the schematics and datasheet…I am not able to get any signal out of this for any current I put through it. Have tried a wide variety of voltage and current seeing from very small upwards to as large as the specs allow. Trying to to see anything, but I don’t. Adjusting vref and gain shows effect, but not relative to whether there is current going through it or not.
Have also bought more than one and tried more than one. Same issue. I am open to it being something I am not understanding but I’ve put in a fair amount of time into this and am not seeing it.
Issue for me with this device is that there are no “getting-started” docs or project samples specific to it…any project-oriented documentation you find has to do either with the ACS712 or another breakout board using it. Of course one can and should be able to extrapolate from that board to this one, but when things don’t work at all, you can not be sure where your problem lies.