Using JFET as magnetic field sensor

[Jdo300]

Hi,

I am wondering if it is possible to switch a JFET on and off with a pulsed magnetic field. A friend of mine was playing around with a circuit where we was using some Hall sensors to trigger coils on and off. When I asked him for the part numbers for the hall sensors, he told me ECG94. When I looked that up, all I found was something about a voltage regulator and a JFET. Maybe he just misread the package but could it be possible that he is able to magnetically switch his coils on and off using JFETS?

Thanks,
Jason O

 

[rbj]

i think the Hall effect is useful for differentiating between negative charge carriers with positive mass (electrons) and positive charge carriers with effectively postive mass (holes). unless the two pads for the gate are separately connected to their own terminals on the FET, i am not sure how you would be able to measure a change of magnetic field (that would result in a potential difference between the "top" pad and the "bottom" pad).

 

[Jdo300]

Actually, if I could, I would be happy with using the magnetic field simply to switch the FET on and off... like a trigger. Is that possible?

 

[rbj]

Actually, if I could, I would be happy with using the magnetic field simply to switch the FET on and off... like a trigger. Is that possible?

i'm not sure how a constant magnetic field could do it without making some kind of amplifier for the measured voltage difference (Hall effect) since, if a coil were just hooked up between the gate and drain, you would need a voltage from a changing magnetic field to turn off an FET.