Subject:
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Re: DCC for the RCX
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Newsgroups:
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lugnet.trains
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Date:
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Thu, 29 May 2003 03:49:06 GMT
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Viewed:
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2353 times
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> As I run 12v stuff I dont know the 9v motor good enough to comment on the
> capacitors but I dont think it's that good an idea to use a resistor to drop > the voltage. Use one or more (zener)diode's instead.
Resistors work fine due to the relative difference in cost. The accessory
outputs of the earlier decoders are 100ma or so @28V or less, so at most you are
dealing with 2.8 w loss (or 100 ma current draw). In order to drop from 14V to
9V, you are loosing 5V/.5W at 100ma, (and 50 ohms) which is not really a
signifigant load. The more recent decoders with 500 ma accessory outputs are
trickier, since you are getting into more serious power draws (like 14 w, which
is darn'd near what my soldering iron is...)
James Powell
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Message has 1 Reply:
 | | Re: DCC for the RCX
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| (...) Huh??!? Your basic resistor can only handle 1/4 watt (0.25W), so your worst-case 2.8W is more than ten times the rated maximum current. Even dumping an "insignificant" 0.5W across a resistor is probably not adviseable unless you are also (...) (21 years ago, 29-May-03, to lugnet.trains, FTX)
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Message is in Reply To:
| | Re: DCC for the RCX
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| (...) As I run 12v stuff I dont know the 9v motor good enough to comment on the capacitors but I dont think it's that good an idea to use a resistor to drop the voltage. Use one or more (zener)diode's instead. Esger (21 years ago, 28-May-03, to lugnet.robotics.rcx, lugnet.trains)
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