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Project: Night Buzzer

Discussion in 'Electronic Projects' started by zachtheterrible, Jan 14, 2005.

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  1. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Your battery is only 9V isn't it? 9V isn't going to shock you. The capacitor won't charge to a voltage higher than the battery.
    Your skin is a high resistance that needs a high voltage to cause a shock. The high voltage on your high skin resistance causes enough current to shock you. A capacitor can make a high current but with only 9V the resistance of the load needs to be very low to cause a high current.
     
  2. Hero999

    Hero999 Banned

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    If the capacitor is large enough it could burn you though.
     
  3. loveangel4943291

    loveangel4943291 New Member

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    loveangel4943291@yahoo.complz i want to find a design for counter which count the number of papers go out from the copy machine and stored the number of copies in small memory plz tell me ur suggestions about this project
     
  4. dave

    Dave New Member

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  5. hartc2697

    hartc2697 New Member

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    Not able to get circuit to turn on/off

    I'm not able to get the circuit to pulse on/off as I would expect. Rather it constantly stays on. Do I have the wrong expectations of this circuit?

    I had thought this circuit created a pulsing of beeps.
    If I'm wrong, could someone point me in a direction of how do accomplish the pulsing chirps? Thanks in advance.
     
  6. tyeo000

    tyeo000 New Member

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    whats the voltage on those caps?
     
  7. uzzors2k

    uzzors2k New Member

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    Above your supply voltage, so 2 volts and up.

    Does it work otherwise? Turn on after some time in the dark and turn off in light? If so you'll need a different kind of buzzer. You're not using a speaker are you?
     
  8. tyeo000

    tyeo000 New Member

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    oke-poke

    uhh...
    noob question but i cant get it to werk at all... :sad:
    im using a 3904 and a 4011 as the transa. is this wrong??
     
  9. Jhoneil Dan

    Jhoneil Dan New Member

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    what would be the values of the capacitors being used to this project?
    please send me a reply as soon as possible coz i want to do it as my project in my electronic subject....
     
  10. scotchbrite

    scotchbrite New Member

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    i used 2 bf194 transistors n a 9 volts battery......the circuit din work.....can some1 plz help me out
     
  11. audioguru

    audioguru Well-Known Member Most Helpful Member

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    As we discussed here, the circuit is poor because it is missing a very important current-limiting resistor. With a 9V battery instead of the original 1.5V the excessive current probably destroyed the 2nd transistor's base-emitter the moment the battery was connected.
     
  12. Oznog

    Oznog Active Member

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    I made one substantially more evil. It was a really high frequency whine and at the higher frequencies it's almost impossible to locate the source in a closed room.

    It was designed so it went off after being in the dark several minutes, ran for under a sec, and repeated every few min. 10 sec is way too short a period and they will immediately realize it's associated with light which blows the whole gag. Several minutes and they will not realize it. You just need to make sure the period is not so long that they might fall asleep without hearing it or maybe only hearing it once, which may not arouse their interest in finding the source of the noise. So a period under 10 min is desirable.

    Ideally the period should be substantially longer at first when the lights go off, giving them a feeling that the problem has gone away.
     
  13. ishank thandi

    ishank thandi New Member

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    hi,
    ok provide me the PCB of NIGHT BUZZER.
     
  14. HiTech

    HiTech Well-Known Member

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    OMG! How these off-topic, bizzare requests get injected here is beyond me!!! LMAO!:confused: :p
    [kneels down with head bowed] "God in heaven, please don't allow these people to reproduce. In all your perfectness, I fail to understand how these amoeba-like people manage to durate on this planet." Amen!
     
  15. HiTech

    HiTech Well-Known Member

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    [​IMG]
    By the time you muster up a PC board, you could have this simple circuit breadboarded a dnworking in half the time.
     
  16. casdon56

    casdon56 New Member

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    Pls I Will Like To Try This Hence Its Fun But Am Just A Beginner Can I Have A Simpler Diagram And A Better Guide To Construct It. Also The List Of The Components
     
  17. snareklutz

    snareklutz New Member

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    I've attached a PCB board for the buzzer. Somebody please check if it works.
     

    Attached Files:

  18. pasanlaksiri

    pasanlaksiri Member

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    Ha ha haaaaaa. This is funny CCT. OMG Its very very funny. Hmm one of my friend is very mad at me now. Coz of this. Hi hi heeeeee.
     
  19. tanmaysathe

    tanmaysathe New Member

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    It will be very difficult to find out the circuit in dark if you choose a buzzer with frequency more than 5KHz.
     
  20. nightcatz

    nightcatz New Member

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    can I use S9014 transisistor

    hello there,
    can I use s 9014 which is an npn silicon transistor as I am not able to find 2n 3904 at my place ....I have got a few s 9014 can I use them
     
  21. kaibui

    kaibui New Member

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    which LDR do you use?
     
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