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Can anyone explain to me how the 555 IC works in the Earth Measurements Project? — Parallax Forums

Can anyone explain to me how the 555 IC works in the Earth Measurements Project?

ArchiverArchiver Posts: 46,084
edited 2002-01-19 00:04 in General Discussion
Quite Confuses me, the capacitor is connected to 1(GROUND) and 2
(TRIGGER) the resistor is in 2(TRIGGER) and 3(OUTPUT), how do this do
the dsicharging and charging, and how this works?

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2002-01-19 00:04
    At 01:28 PM 1/17/02 +0000, mysemicon2000 wrote:
    >Quite Confuses me, the capacitor is connected to 1(GROUND) and 2
    >(TRIGGER) the resistor is in 2(TRIGGER) and 3(OUTPUT), how do this do
    >the dsicharging and charging, and how this works?

    The output is inverted from the input: when the voltage on the cap is LO,
    the output is HI and the cap charges thru the resistor. When the threshold
    voltage is reached (2/3 Vcc), the output goes LO and discharges the cap via
    the resistor.

    Its similar to the standard circuit but requires 1 less resistor and can
    provide a more accurate 50 duty cycle *IF* the '555 is one of the CMOS
    variants.

    dwayne



    Dwayne Reid <dwayner@p...>
    Trinity Electronics Systems Ltd Edmonton, AB, CANADA
    (780) 489-3199 voice (780) 487-6397 fax

    Celebrating 18 years of Engineering Innovation (1984 - 2002)

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