Subject:
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Re: LEGO Electro-magnet
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 20 Apr 2001 14:29:45 GMT
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Viewed:
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1578 times
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To be more precise: in passive mode there is a 10K pullup (to 5V)
introducing some current (0.45 mA) in the coil. This small current may be
enough to retain something stuck to the magnet...
Philo
> > A last question for the use of input ports: will the remaining magnetization
> > caused by the 10k pullup in passive mode be low enough to release payload ?
>
> Not sure, (I'm not an electrical-engineer please Andreas Peter, help :) )
> But, when the coil has a consumption of 9mA at 9V it's 1k. (81mW)
> So if I undestand it right, you're in parallel with your 1k coil to a 10 k
> pull-up, right ? Resistance of this parallel resistors is less than 1k at 5V,
> right ?!? So somewhat more than 5mA -> 25mW ?!?
>
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Message has 1 Reply:
 | | Re: LEGO Electro-magnet
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| (...) I think this could happen. Even without this low current present all the time, an electro magnet powered by a DC supply always in the same direction can develop a residual magnetic field (samll things would stay stuck even after the electro (...) (23 years ago, 21-Apr-01, to lugnet.robotics)
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Message is in Reply To:
| | Re: LEGO Electro-magnet
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| Hi Philippe, (...) Hmm, I guess they are NOT protected. (...) Not sure, (I'm not an electrical-engineer please Andreas Peter, help :) ) But, when the coil has a consumption of 9mA at 9V it's 1k. (81mW) So if I undestand it right, you're in parallel (...) (23 years ago, 20-Apr-01, to lugnet.robotics)
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