I'm using the hall effect sensor A1301EUA-T, I'm feeding it with 5V. At the VOUT output when there is no magnetic field there is 2.5V. When approaching the NORTH POLE of the magnet VOUT ranges from 2.5 up to 5v. When it approaches the SOUTH POLE of the VOUT magnet it varies from 2.5 up to 0v. To have a variation in VOUT from 0v to 5v I need 2 magnets, move one away and bring the other closer. My question is: how do I have a variation in VOUT from 0v to 5v approaching just one magnet, that is, I want it when I have no magnetic field close to the sensor I have 0v in VOUT?

Here is my circuit:circuit


1 Answer 1


Subtract 2.5 volts and apply a gain factor of two. This can be done quite easily with an opamp but it's likely you'll need a negative supply to reach precisely 0 volts and a positive supply greater than 5 volts to reach an output of 5 volts.

  • \$\begingroup\$ @Trevor: That's "bear in mind". The mis-spelling usually appears on this site as "bare with me" which reads as an invitation to undress together. Definition: bear bɛː verb, support; carry the weight of. I know you'll care! \$\endgroup\$
    – Transistor
    Commented Aug 23, 2017 at 19:36
  • 1
    \$\begingroup\$ @Transistor sigh.. thanks I have always had an issue with homophones, and too lazy to go check for this... \$\endgroup\$
    – Trevor_G
    Commented Aug 23, 2017 at 19:40
  • \$\begingroup\$ +1. I'd add, "bear in mind, you will be more susceptible to stray magnetic fields with this mechanical/magnetic arrangement." \$\endgroup\$
    – Trevor_G
    Commented Aug 23, 2017 at 19:46
  • 1
    \$\begingroup\$ Now that's betterer by myles. \$\endgroup\$
    – Andy aka
    Commented Aug 23, 2017 at 20:19

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