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Timer circuit

Discussion in 'General Electronics Discussion' started by Chickwolf, Mar 9, 2014.

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  1. Chickwolf

    Chickwolf

    36
    0
    Jan 3, 2014
    Hey guys.
    I have recently come across a timer circuit using a 555 IC that I was interested in building but I am unsure of some of the connections and the layout of the diagram.
    I have attached the diagram as a thumbnail for a reference.
    Basically, I understand the relationship between R1 and C1 and how they are responsible for controlling the pulse out, but im not sure about what pin 2 would be connected to deliver the pulse input, what pin 3 would be connected to so show the pulse out and also how the circuit would look when the IC connections are laid out correctly (how they would appear on the chip). I have not done any work on circuits when they are drawn out like this so im unsure of how to proceed.
    Thanks in advance for any help.
    Chick
     

    Attached Files:

  2. cjdelphi

    cjdelphi

    1,096
    104
    Oct 26, 2011
    Pin 2 detects a low signal, from ground which fires off the 555 (eg from a button)
     
  3. signalman72

    signalman72

    57
    6
    Jan 26, 2014
    What are you wanting to do, purpose wise? It looks like you have it configured for monostable, or one-shot operation. It needs a pulse such as a signal or simply a push button switch input into pin 2. IIRC, the resistor/capacitor relationship dictates output duration. You can also Google the pinout to see how the pins would be connected in a practical manner.
     
    Last edited: Mar 10, 2014
  4. Chickwolf

    Chickwolf

    36
    0
    Jan 3, 2014
    In regards to the purpose, there is nothing that it is being built to be used for, I am simply building it so that I can practice using a breadboard. I understand it set up for a "one-shot use" but as I am just using it for test purposes, it doesn't really matter to me.
    If pin 2 were to be connected to a push switch of some description, would it matter where the other terminal of the switch were to be connected? Or would it have to be placed near as possible to the power source? As for pin 3 being the output, that could be connected to a LED for a simple output couldn't it?
    Cheers for the help guys.
     
  5. shumifan50

    shumifan50

    576
    57
    Jan 16, 2014
    If you are just trying to learn, then connecting the output to a scope would be more beneficial as you can measure the timing of the output.
     
  6. signalman72

    signalman72

    57
    6
    Jan 26, 2014
    A little project I've been messing with involving a 555 timer is to provide a clock pulse to a 4017 decade counter. It would probably be a good way for you to get your feet wet also. You can advance the counter by one using the 555 configured as a one-shot. You can also have a free running counter by configuring the 555 in astable mode. The 4017 can drive up to ten LEDs, so it gives you a fun circuit to build that shows an example of how the 555 can be utilized.
     
  7. cjdelphi

    cjdelphi

    1,096
    104
    Oct 26, 2011
    Chickwolf, to trigger the ic, pin 2 goes to negative. (Simply connecting this wire to negative)

    Pin 3 goes to your led (with a 300ohm resistor) (long leg)
    - goes to ground / negative .... (short leg)
     
  8. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,271
    Nov 28, 2011
    There's information on the 555 all over the net. This one looks good: http://electronicsclub.info/breadboard.htm

    It shows you how to connect a pushbutton and a pullup resistor to pin 2 so you can trigger the monostable by pressing the button, and how to connect an LED with a current limiting resistor to pin 3 so you can see the output of the monostable.

    It also shows you clearly how the pins are numbered, and how to lay out the circuit on a breadboard.
     
  9. Chickwolf

    Chickwolf

    36
    0
    Jan 3, 2014
    Thanks for the advice guys, this has really cleared up the subject for me!
     
  10. Jibby

    Jibby

    15
    0
    Sep 12, 2013

    Please refer the attachment
     

    Attached Files:

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