Electronics Clock

Discussion in 'Modding' started by bard, 15 Jun 2003.

  1. bard

    bard Modding isn't what it used to be

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    A friend of mine, BakkiZ, has this old circuit from a clock. He showed me that when he connected the circuit to a battery, and connected two other wires from the circuit to a speaker, the speaker made a click every second. This made me thinking that there must be some kind of signal coming out of the circuit, that could be used to flash an LED every second. There are four wires coming from the circuit, two of which are power wires (+ and -) and the other two are those that give the signal. Would this circuit work for making the LED flash every second? And if it wouldn't work, please explain to me what can be done to make it work.
    [​IMG]

    I'm a "n00b" when it comes to electronics, hence I want an explanation if it is wrong.
    BakkiZ is quite good, though. He has been studying electro for a year now.
     
    bard, 15 Jun 2003
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  2. cpemma

    cpemma Ecky thump

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    I'd guess the clock circuit is something like on the left, so one of the speaker wires will be connected to one side of the battery.

    Either way, take the most positive speaker wire to Ax, other to Bx.
    Any little transistor will do, NPN or PNP, use the appropriate circuit.

    [​IMG]
     
    cpemma, 19 Jun 2003
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  3. NiHiLiST

    NiHiLiST New-born car whore

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    Just thought I'd add that it's fairly simple to make a circuit that will output a pulse every second (or any other amount of time for that matter) that would DEFINATELY work so long as you can solder a few components onto some stripboard.
     
    NiHiLiST, 20 Jun 2003
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  4. bard

    bard Modding isn't what it used to be

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    Thanks, so the circuit I drew up was right except for that I don't have the 1K resistor on A? And what purpose serves this resistor?

    Nihilist, I know it's easy to make a circuit that pulses about once every second, but this circuit pulses exactly one time every second. (I guess that could be achieved with a timer chip as well, but I don't have any).
     
    bard, 20 Jun 2003
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  5. NiHiLiST

    NiHiLiST New-born car whore

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    Okay, just thought it was worth mentioning in case you didn't know :)
     
    NiHiLiST, 20 Jun 2003
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  6. Smilodon

    Smilodon The Antagonist

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    the resistor is to prevent the base on the transistor to fry...

    a transistor can only handle about 0.6 to 0.7 on it's base so if you give it more it will fry...
     
    Smilodon, 20 Jun 2003
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  7. cpemma

    cpemma Ecky thump

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    More a current limit than voltage, if the load is shorted, the base current can only rise to V/R, (1.5-0.6)/1000, about 1mA, which will limit the collector current and won't damage the tranny .

    Linear's done a post on base resistors recently. :search:
     
    cpemma, 20 Jun 2003
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