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Protection Resister — Parallax Forums

Protection Resister

TomSTomS Posts: 128
edited 2005-11-27 19:05 in BASIC Stamp
I want to protect multiple 3-state outputs connected to a bs2p and want to protect everything in case two outputs should come on at the same time. What is a good range of values for the series resister.

Thanks
Tom

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-11-26 18:00
    Tom,

    ·· Assuming you're only talking to other 5V devices, then 220 ohms is a good value to use.

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    Chris Savage
    Parallax Tech Support
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  • allanlane5allanlane5 Posts: 3,815
    edited 2005-11-27 19:05
    Yes, the BS2 pin can take about 25 mA before burning out. If you put in a series 220 ohm resistor, and tie a +5 high output to a low (zero volgs) output (so they fight each other) a 220 ohm resistor will limit the current to (5 / 220 == 22.7 mA) and thus protect your BS2.
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