I bought ACS711 current sensors I’m starting to test them.
When I apply current and turn on the sensor it gives me 2.5674 volts at the output. But if I increase the voltage, the current does not increase, or if I decrease it, it does not decrease.
note the volt is very small and i applied ampere up to 10 amp ac
Could you tell me which ACS711 you purchased (i.e. -12.5A to +12.5A or -25A to +25A)? Also, could you post a diagram of how you have it connected? How are you measuring the sensor output voltage?
In your first post you mentioned that you were trying to measure an AC current. If that is the case, you should not expect to get a DC voltage output from the sensor. Instead, you should see the voltage vary sinusoidally along with the current. This is not something you will be able to see with a multimeter; you will have to use an oscilloscope or a properly programmed microcontroller (sampling at well over the AC frequency) to see it.
The output voltage is directly a function of the instantaneous current passing through the sensor. The full explanation of the output and how to calculate it can be found on the product page.
As it is mentioned in the datasheet of ACS711, Output voltage is proportional to AC or DC currents.
The sensor has an operating voltage of 3 – 5.5 VDC and an output sensitivity of 110 mVDC/A when Vcc is 3.3 V (or 167 mVDC/A when Vcc is 5 V).