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This may sound like a silly question, but it got me thinking.

Apart from my lab at work, I have an electronic workbench at home. Most of my components are stored in small, plastic cylindrical jars (imagine the ones used for storing medical pills, something like that). I have a lot of those so I store all my resistors, capacitors and small package ICs in those containers. The problem is that the containers are all around the place, and even keeping them in a boxes makes it hard to find anything.

So my idea was to glue a small permanent magnet at the bottom of each jar and then put them on a metal surface (like a white board, or just a metal bar mounted on the wall).

However I was wondering if the magnet would have an impact on the components inside the jars. I had cases where transistor leads were attracted by magnets (no idea why, since they are supposed to be copper). I was about other drawbacks of such a solution, like maybe the components could get magnetised and would attract each other when assembling a PCB - that would be annoying.

So... Could you share your concerns regarding such a solution? Should I worry about the magnetic field?

  • There is also induction to consider. I mean, a conductor in motion near a magnet will experience an induced EMF. If the magnitude of the EMF is large enough, could it damage some components? I have no idea if it could be a serious problem. I am just throwing it out there. – user57037 Jul 05 '16 at 16:21

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Many transistors (and other through-hole components) are made with tin/copper plated steel leads to save on copper, that's why they are attracted by magnets. Static magnetic field won't have noticeable effect on transistors themselves, but residual magnetic field can affect sensitive components nearby, like hall sensors or reed relays. This is especially important if you tend to make high-density designs, you're unlikely to notice any effects at all if your components are a couple centimeters apart.

Also, as @mkeith said in his comment, designs with moving parts may exhibit some interference from induced EMF. Again, this is unlikely to be noticeable unless you have compact design and parts of it are moving or spinning very fast. Most probably, motors used in such design will produce much more interference than residual magnetism on transistor leads.

Needless to say, sensitive components themselves should not be stored near magnets.

Dmitry Grigoryev
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    The poser was worrying about the effect of magnetism on basic components. In regards to this, can you explain what you mean by the 'sensitive components'? – soosai steven Jul 06 '16 at 17:10