/elec/propeller-clock

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  • Committer: edam
  • Date: 2011-11-04 15:07:26 UTC
  • Revision ID: edam@waxworlds.org-20111104150726-0evv5cetrckzg9do
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electronics-information
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+12V and GND rails to prevent a lot of current flowing.  Lets work
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this out (lets suppose that R is 1 ohm).
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        V = IR, therefor I = V/R
 
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        V = IR, therefore I = V/R
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        P = VI = V(V/R) = (V^2)/R = ( 12 ^ 2 ) / 1 = 144W
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        P = VI, therefor I = P/V = 144/12 = 12A
 
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        P = VI, therefore I = P/V = 144/12 = 12A
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That's a lot of current and a lot of power, flowing continuously, just
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to provide 6V!
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Wiring up multiple LEDs in parallel to a single arduino pin
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===================================--======================
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Image we have
 
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Imagine we have this
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             |
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    Arduino  |     ___        ,,
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            o-----|___|---+---►|---.
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             |      R     |   D1   |
 
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             |       R    |   D1   |
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             |            |        |
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             |            |   ,,   |
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             |            '---►|---+--- GND
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So, imagine we have this instead
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             |
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    Arduino  |        ___        ,,
 
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    Arduino  |        ___     ,,
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            o----+---|___|----►|---.
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             |   |     R1     D1   |
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             |   |                 |
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                           ▼  D1
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                           ¯``
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                           |
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             |             |
 
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                           |
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             |             ▼  D2
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             |             ¯``
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             |             |
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             |             +-------+-------'
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             |             |
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    Arduino  |    ___    ,-|
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            o----|___|--(|< )
 
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            o----|___|--(|< ) T
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             |     R1    `-|
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             |             |
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             |             '----- GND