# How does an electric compass work?

**URL:** <https://boards.straightdope.com/t/how-does-an-electric-compass-work/55170>\
**Category:** Factual Questions\
**Created:** [February 20, 2001, 3:07am UTC](https://boards.straightdope.com/t/how-does-an-electric-compass-work/55170 "2001-02-20T03:07:05Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Xenopus](https://avatars.discourse-cdn.com/v4/letter/x/49beb7/32.png) [@Xenopus](https://boards.straightdope.com/u/Xenopus)\
**Post date:** [February 20, 2001, 3:07am UTC](https://boards.straightdope.com/t/how-does-an-electric-compass-work/55170/1 "2001-02-20T03:07:05Z")

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I came across a small pocket digital readout compass the other day. It appeared to be completely electronic, with no moving parts.

How is this thing measuring the magnetic field, and determining its polarity?

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**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\
**Post date:** [February 20, 2001, 4:02am UTC](https://boards.straightdope.com/t/how-does-an-electric-compass-work/55170/2 "2001-02-20T04:02:22Z")

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The subject you want to look up is “Hall Effect”:

[http://www.britannica.com/bcom/eb/article/3/0,5716,39723+1,00.html](http://www.britannica.com/bcom/eb/article/3/0,5716,39723+1,00.html)

Now, what I want to know is why the little handheld hiker’s gps unit I have can’t incorporate a digital compass as well.

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**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\
**Post date:** [February 20, 2001, 4:06am UTC](https://boards.straightdope.com/t/how-does-an-electric-compass-work/55170/3 "2001-02-20T04:06:05Z")

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vb’s parser thinks the commas are terminators:

[try this](http://www.britannica.com/bcom/eb/article/3/0,5716,39723+1,00.html)