I’m using a reed switch in a circuit with a 12V 500mA power supply.
Rees switch data states 1A and 200V
When I check the resistance across the reed switch with a multi-meter I can see
the resistance change when close to a magnet. As expected, but the multi-meter is
a bit slow to respond so I replied it with a 12V light bulb connected to the power supply.
The light comes on when a magnet is near the reed switch, as expected, but it stays on!
I have tried a couple of reed switches with the same result.
Can you help please?
Dick
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Hi Dick
What size (Watts) light bulb.
Cheers Bob
Another thing. Exactly what are the reed switches. I think some of them latch and the magnet polarity has to be reversed to unlatch.
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Hi Dick,
Looks like you’re not the first to wonder, and there are a few mechanism that can contribute:
Good catch by Robert, if you can link to your reed switch’s product page, that’ll be super helpful
Maybe measuring the current through the switch will reveal something?
-James
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Hi Robert, I can’t tell, its and old bulb from my HR holden head light!
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That might be as high as 55W. 4.6A. If your power source has supplied this it could well be the end of your reed switches. 12V + 1kΩ + LED would be a better option (and safer).
Cheers Bob
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Ahhh thanks Bob, yep the reed switch is car-put!
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