Help with ne555 for lamp

Discussion in 'General Electronics Chat' started by PN3423, Jul 28, 2008.

  1. PN3423

    Thread Starter New Member

    Jul 28, 2008
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    Hi, I'm new here and also very new to electrical engineering
    I'm having problems with a circuit where i'm supposed to make a lamp with a timer and the timer will control the duration of the lamp in "on" condition. Now the problem is that the timer is monostable ne555 and i know nothing about this circuit part. How does it basically work to control the duration of the lamp? and could anyone give ideas (with picture if possible) on how this circuit is going to be? thanks
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    Is this a homework assignment?

    Have you looked at data sheet for a 555? They include schematics for what your talking about, the only thing you need to add is a relay. Personally I would use a SSR (Solid State Relay), it is much simplier overall to use.
     
  3. PN3423

    Thread Starter New Member

    Jul 28, 2008
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    well, it's more like a project.
    o, which datasheet would be more relevant to my project, i found quite much datasheets from browsing. And what would a relay do? would they control the timing duration of the lamp or for other purpose?
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    Look up the monostable diagram, and work from there.

    A SSR will connect directly to the output of the 555, it can drive them without any extra gadgets. It turns on the 120VAC, it is a switch. Think how a regular lamp is wired, the switch turns on and off the hot wire.

    How familiar are you with basic electricity?
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    Bill, what's an SSR? Did you mean SCR?

    Actually, I think we first need to acertain what are the specifications of the lamp (volts, current, incandescent, LED, other) that the OP needs to control.

    If the lamp is an LED, it's duck soup. :)

    If it's a 120V, 250W floodlight, that's a whole 'nother critter.

    So, what kind of light are you needing to control? What are it's specifications?

    Here is a good tutorial page on the 555 timer:
    http://www.uoguelph.ca/~antoon/gadgets/555/555.html
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    Nope, I defined it in my first post, a Solid State Relay, which is a optocoupled triac. You don't need to know this to use them though, they are pretty simple.
     
  7. silvrstring

    Active Member

    Mar 27, 2008
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    Here is a basic drawing of monostable 555 and how to manage pulse width.

    Hope it helps.
     
  8. PN3423

    Thread Starter New Member

    Jul 28, 2008
    3
    0
    For Bill :well, i'm a student from mechanical engineering and now studying electric power engineering course, and learned very little about electronics before taking the course, the lecturer didn't give much helpful solution.
    By the way, thanks for the replies but now i want to ask another thing, where i must place a battery charger for a battery powering the timer? Will it work as AC-DC converter? or must I put a diode(some friends said it was for reducing voltage)?
    Oh yeah i forgot to state that it was using AC power for the lamp and DC for the timer(battery), can anyone explain how to draw this circuit? because i haven't got any clear vision of how it is going to be
     
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