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Anyone Know about 555 timers!?

Discussion in 'General Discussion' started by Oracle, 13 Apr 2006.

  1. Oracle

    Banned

    Joined: 17 Jan 2006

    Posts: 1,971

    Location: Haskins

    I'm looking for a schematic that would show a 555 timer energising a relay for a period of two seconds every 10 seconds using a capacitor rated at 10 micorfarads.

    I'm aware of all the relevant pins on an IC 555 chip but could just do with some help locating a diagram of this...

    It would also be handy if one terminal of the relay coil is connected to 15v DC

    Thanks
     
  2. PikeyPriest

    Wise Guy

    Joined: 21 Jun 2004

    Posts: 1,186

    T = 0.7 × (R1 + 2R2) × C1
    and f= 1.4/(R1 + 2R2) × C1

    T = time period in seconds (s)
    f = frequency in hertz (Hz)
    R1 = resistance in ohms (ohm)
    R2 = resistance in ohms (ohm)
    C1 = capacitance in farads (F)

    Mark time (output on): Tm = 0.7 × (R1 + R2) × C1
    Space time (output off): Ts = 0.7 × R2 × C1

    Put in the capacitor values and play around with what resistances can give you those times.

    Diagrams of the circuit your looking for are on:
    http://www.kpsec.freeuk.com/555timer.htm#astable

    Look for the 555 Astable design and just above it on how to hook the relay up

    From what i remember the relay can switch absolutely anything its rated for as part of a seperate circuit.
     
  3. Goliath

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    Location: The Republic

  4. Oracle

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    Gangsta!! :D
     
  5. Oracle

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    How can I test it to check the timing!? a bulb or something!? (or buzzer)
     
  6. PikeyPriest

    Wise Guy

    Joined: 21 Jun 2004

    Posts: 1,186

    any LED/buzzer/light will be fine