Basic Hall effect question

[Parksy]

Hi all

Quick question on Hall effect ignition systems. Which way does the magnet have to face the sensor? Does it matter? I've got some small disc shaped neodymium magnets which I intend to use, are the flat sides the N and south poles? Does the flat section need to face the sensor? Or will any way suit?

Thank you all

Andy

 

[gbritnell]

It depends on the type of Hall transistor you are using but generally they are activated by the when the south pole of the magnet passes by. Yes the flat sides are the pole sides. I have several magnets in store for when I need them.
I tested them with a wired up Hall setup to see what pole was which and then marked them with an ink marker.
gbritnell

 

[Charles Lamont]

A compass will tell you which magnet pole is which.

 

[mayhugh1]

A compass will tell you which magnet pole is which.

And remember, if you're looking for the south pole of your magnet, the north end of your compass needle will point to it. - Terry

 

[Parksy]

Thanks guys. I appreciate it. I was hoping to simply drill a hole into the side of an aluminium disk and insert the magnet. If I have to mount it into the hole sideways I may have to make a carrier which I can insert into the hole.

 

[Gordon]

Thanks guys. I appreciate it. I was hoping to simply drill a hole into the side of an aluminium disk and insert the magnet. If I have to mount it into the hole sideways I may have to make a carrier which I can insert into the hole.

You do not want it mounted sideways. You want the south pole pointing out and north pointed into the center.

 

[Parksy]

You do not want it mounted sideways. You want the south pole pointing out and north pointed into the center.

This is what I meant. I wasn't very clear with my previous post.

 

[Parksy]

Thanks all for your help. I used a cup of water and some styrofoam and placed the magnets on the foam on the water to work out which poles were which. Couldn't find a compass anywhere.