Hall sensor A3144

[rsfoto]

Hi,

I found some A3144 in my boxes and wanted to test the behaviour. I wired it according to the following diagramm.

I read in the datasheet that the output can be as hi as the input voltage but my tests did not give me that value.

I powered it with 5V and with no magnet present it gave me ~1V and with a magnet close to it it raised to ~2V but not near the ~5V I was feeding.

Is the output dependent from how strong the magnet is?

Thanks Rainer

PD I do not know if those are really A3144 because the marking on the front is 743ZF and on the bottom it says +ALEA. Are those FAKE? or what are they?

[Shay]

Hi,

I found some A3144 in my boxes and wanted to test the behaviour. I wired it according to the following diagramm.

I read in the datasheet that the output can be as hi as the input voltage but my tests did not give me that value.

I powered it with 5V and with no magnet present it gave me ~1V and with a magnet close to it it raised to ~2V but not near the ~5V I was feeding.

Is the output dependent from how strong the magnet is?

Thanks Rainer

PD I do not know if those are really A3144 because the marking oin the fron is 743ZF and on hte b ottom it says +ALEA. Are those FAKE? or what are they?

From the datasheet it seems like it is open collector. So you should either get ~0.2V to VCC.
Make sure that you have a 10K resistor, and try a different hall.

[TimFox]

That sensor, with open-collector output, is an active circuit (Schmitt trigger with hysteresis) driven from the Hall-effect element.
There would be a minimum value of magnetic field at the sensor to guarantee logic-1 (high) output.
Depending on the exact model  https://www.alldatasheet.com/datasheet-pdf/download/55095/ALLEGRO/A3144EU.html
the "operating" field value B_op is somewhere between 50 and 450 Gauss, and the "release" field value B_rp is somewhere between 10 and 430 Gauss, with typical hysteresis between values of 55 Gauss.
Without a resistor on the output to +5V, the output will always be lowish.