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 08:45:18 GMT
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Viewed:
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1720 times
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Hi Philippe,
In lugnet.robotics, Philippe Hurbain writes:
> Hello Rainer,
>
> True! But simplicity sometimes takes a long time to be acheived ;)
>
> But there may be some use in flyback and series diodes: Andreas says that
> his magnet consumes 9mA, below what is available through sensor ports in
> active mode. So a magnet could be also commanded through these ports,
> switching from active(light) sensor type and passive(touch) sensor type.
> These ports are probably not so much protected for inductive loads.
Hmm, I guess they are NOT protected.
> 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 ?!?
I may be completelly wrong, but than we will be corrected and get the right
result ;-)
Regards,
Rainer
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Message has 1 Reply:
 | | Re: LEGO Electro-magnet
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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 (...) (24 years ago, 20-Apr-01, to lugnet.robotics)
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Message is in Reply To:
| | Re: LEGO Electro-magnet
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| Hello Rainer, True! But simplicity sometimes takes a long time to be acheived ;) But there may be some use in flyback and series diodes: Andreas says that his magnet consumes 9mA, below what is available through sensor ports in active mode. So a (...) (24 years ago, 20-Apr-01, to lugnet.robotics)
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