control 12v circuit with hall sensor

I have a hall sensor that outputs 0.2-2.5v in a linear fashion. I would like to turn on a 12v circuit when the sensor outputs more than 0.5v or so then turn off when the voltage falls below 0.5v.

Preliminary research suggests that i could use a transistor that would turn on with about 0.7v base voltage but i have no idea how to wire it or what type of transistor to use. i would also consider using a transistor to drive a relay that actually does the switching since the 12v load is about 5w.

by davegus91
September 09, 2017

Better to use a comparator, you have better control of the trigger voltage. More information at

by mikerogerswsm
September 18, 2017

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