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Square wave generator what?

  1. Aug 19, 2011 #1
    Square wave generator....what?

    Okay, so I built a square wave generator using a 555 timer and schematics that I found off the internet. Upon completion, I dumbly realized that there is only an output. I wanted to use the square wave generator in resonance inductive circuit, but seeing as there is only an output, how would I be able to work it into the circuit? If not, how would it be used?
  2. jcsd
  3. Aug 19, 2011 #2


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    Re: Square wave generator....what?

    You can take the output between the negative terminal of the supply and the "output" pin (pin 3) of the 555.

    Could you explain what your mean by "resonance inductive circuit" ?

    If you mean a series tuned circuit, then the 555 can drive such a circuit directly, although 555s normally generate quite low frequencies and tuned circuits for such frequencies would have large expensive inductors in them.

    By using small value components in the timing for the 555, they can be operated up to 500 KHz or so. Maybe higher.
  4. Aug 24, 2011 #3
    Re: Square wave generator....what?

    Thank You! I know I didn't really word "resonance inductive circuit" correctly; I meant inductive coupling. I want to be able to create an inverting current using a 555 timer and dc current (such as a battery) to power an electromagnetic induction coil. And isn't the output pin pin#6? I guess it might depend on the manufacturer.....
  5. Aug 24, 2011 #4


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    Re: Square wave generator....what?

    No, the output is always pin 3.

    You probably need a circuit like this:


    This shows a lamp in the collector circuit of a power transistor, but you would need the primary of a step-up transformer to be there instead.

    This one is possibly more like what you would need:

  6. Aug 30, 2011 #5
    Re: Square wave generator....what?

    I think I must be misreading something..... but where is the power supply (in image 1)?
    Last edited: Aug 30, 2011
  7. Aug 30, 2011 #6
    Re: Square wave generator....what?

    The 555 will not give you a true 50% duty cycle square wave, which you need to do precision electrical measurements. The 555 output should be put through a good divide by 2 flip flop.

    Bob S
  8. Aug 30, 2011 #7
    Re: Square wave generator....what?

    Quick note: If you drive an inductor as shown in the first pic above, there'll be high voltage spikes just as the transistor turns off. So you might consider a damping diode (a diode in parallel with the inductor and pointing upward, in the circuit shown)
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