Need Help to find suitable magnetic sensor

[KUMARA SHP]

Hi
I need magnetic sensor, that produce analog voltage proportional to magnetic field.
I found linear hall effect sensors.
http://www.analog.com/media/en/technical-documentation/data-sheets/AD22151.pdf
https://www.diodes.com/assets/Datasheets/AH8502.pdf

But I need ominipolar 1D sensor with analog output. I searched in mouser and Digikey, I could not find that type.
are there any reason for it?

basically I want to control light intensity of bulb which is proportional to the magnetic field strength regardless of North or South pole.
I know I can use bipolar type, but my idea is to control NPN transistor directly from sensor analog output. so I like if I can have omini polar sensor with 0V output at 0 Gauss.

Please help me if you know any type of these sensor?

Thanks
Athula

 

[davenn]

But I need ominipolar 1D sensor with analog output. I searched in mouser and Digikey, I could not find that type. are there any reason for it?

maybe they are just not manufactured

 

[KUMARA SHP]

yes, but why? don't people need analog output voltage proportional to magnetic field regardless of polarity?

could you please check this. it seems like suitable for my requirements, but not sure.
http://www.nve.com/Downloads/analog_catalog.pdf
I am talking about Type AA sensors in above pdf.

Thanks

 

[(*steve*)]

Hall effect is sensitive to the strength as well as the direction of the magnetic field. It is thus not surprising that linear detectors are bipolar.

A precision rectifier could possibly solve your problem, but you need an OP-AMP and several other assorted components.

Maybe you could use 2 sensors and back to back and a pair of diodes to select the output with the highest magnitude. At rest, the output is likely to be mid-rail, that may also be problematic.

 

[KUMARA SHP]

Yes, steve, I thought about OP Amp with transistor, can I directly buy differential amplifier, which will amplify difference but always output is positive, ?
Normal differential amplifier output can go positive or negative, but I need analog circuit that produce absolute value ( |v-v0| ).
are there any such a ICs?

also could you please look at this datasheet, I think I found some solution here. ( Type AA sensors)
http://www.nve.com/Downloads/analog_catalog.pdf

Thanks

 

[(*steve*)]

Precision rectifier. Google it.

 

[Arouse1973]

Hi
I need magnetic sensor, that produce analog voltage proportional to magnetic field.
I found linear hall effect sensors.
http://www.analog.com/media/en/technical-documentation/data-sheets/AD22151.pdf
https://www.diodes.com/assets/Datasheets/AH8502.pdf

But I need ominipolar 1D sensor with analog output. I searched in mouser and Digikey, I could not find that type.
are there any reason for it?

basically I want to control light intensity of bulb which is proportional to the magnetic field strength regardless of North or South pole.
I know I can use bipolar type, but my idea is to control NPN transistor directly from sensor analog output. so I like if I can have omini polar sensor with 0V output at 0 Gauss.

Please help me if you know any type of these sensor?

Thanks
Athula

Have you looked at the Allegro hall devices like the A1324, 5, 6
Thanks
Adam