Questions on Automatic Staircase Light

Discussion in 'General Electronics Chat' started by spidermanIIII, Oct 23, 2014.

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  1. spidermanIIII

    Thread Starter Member

    Nov 22, 2013
    hi, i searched for this project and i found this schematic i have some questions about it what if i remove R1 what will happen i afraid to remove it because i deal with 220 volt , second i tried to do simulation for this circuit but there is error can anyone help me with simulation
  2. Ramussons

    Active Member

    May 3, 2013
    the IC 555 acts as a mono stable and derives its 8.2 Volts power from the 220 V mains. R1 is the voltage dropping resistor which limits the Zener current to about 22 mA.
    If R1 is Removed, the circuit will not work.
    If you bypass R1, the minimum you can expect is a blown Fuse, D1, D2 and maybe an exploded C1.
  3. alfacliff

    Well-Known Member

    Dec 13, 2013
    why not just use a motion detector socket? then it will turn on when anyone is on the stairs, and off after a preset interval.
  4. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    By Pass R1 and 555 will literally explode, The Zener and some caps too.
  5. BillB3857

    AAC Fanatic!

    Feb 28, 2009
    I'm surprised this thread is not closed since it is line operated without isolation. The OP is properly afraid when playing with line voltages. Even those with experience respect it.
  6. Wendy


    Mar 24, 2008
    We close them as we see them.

    This thread is against the AAC forum rules, Chapter 6, as seen here:

    This can be found in our Terms of Service (ToS)
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