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newbie questions on bs2 — Parallax Forums

newbie questions on bs2

ArchiverArchiver Posts: 46,084
edited 2003-11-28 22:44 in General Discussion
hi all

i have heard that pins of bs2 are easy to get burned out.
my question is that do i need to put resistors on all output/input
pins to project them?
what value of resistors is good for protecting pins on any knid of
project with bs2?

thanks

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-11-28 22:27
    At 09:49 PM 11/28/03 +0000, i_drives wrote:
    >hi all
    >
    >i have heard that pins of bs2 are easy to get burned out.
    >my question is that do i need to put resistors on all output/input
    >pins to project them?
    >what value of resistors is good for protecting pins on any knid of
    >project with bs2?
    >
    >thanks

    Generally a 220 ohm resistor is used to protect the I/O pins. That value is
    based on Ohms Law which shows: 5 volts / 220 ohms = 23 ma which is less
    than the individual I/O Port capacity limit of 25 ma.



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  • ArchiverArchiver Posts: 46,084
    edited 2003-11-28 22:44
    No, I don't think that's the case; they're actually pretty tough. That
    said, a direct short can damage a pin permanently. Where the
    opportunity for a programming error to cause a direct short exists we
    suggest a 220 ohm resistor to protect the IO pin. In fact, we build 220
    ohm resistors into the HomeWork board and other student-oriented
    products.

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: i_drives [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=YW-5kbnCgWof5SzW0fBtXCQr1BdbrE_3dwwkdlNyoinHqOcFlG4uisj4sNEvxxCLA9B1X7P1Qt1zJQ]i_drives@y...[/url
    Sent: Friday, November 28, 2003 3:50 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] newbie questions on bs2


    hi all

    i have heard that pins of bs2 are easy to get burned out.
    my question is that do i need to put resistors on all output/input
    pins to project them?
    what value of resistors is good for protecting pins on any knid of
    project with bs2?

    thanks


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