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  1. #1
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    simple square wave generator

    Dear all beginners!

    I've got a simple design for Square Wave Generator with 2 output signals which are time/phase delayed (shifted) each by other.
    Please give description for this design and estimate the period and delay time values.

  2. #2
    LvW
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    simple square generator

    Hi Thanhlongbin !

    In your own interest I recommend to try it first by yourself.
    The design is based on the classical RC relaxations generator principle which is described in a lot of textbooks. By doing this you will gain understanding !



    •   Alt17th July 2009, 08:44

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    cheap and best square wave generators

    Hi LvW,
    Thanks for your recommendation "in my own interest".
    This circuit was my student's work 20 years ago and I remembered it run well.
    Perhaps, I should replace the phase "Dear all" by "Dear all beginners". If so, I would not disturb the people like you.



  4. #4
    LvW
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    squarewave

    Sorry, Thanhlongbin, for the misunderstanding.
    I couldn´t realize that it was your intention to place a task for beginners.
    In fact, I thought you are a beginner. Sorry !
    Best regards
    LvW



    •   Alt17th July 2009, 09:55

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    how to delay a square wave

    how can i design a microcontroller square wave generator with simple delay or PWM so that i can vary the frequency.



    •   Alt17th July 2009, 10:29

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    make your own square wave

    Thanhlongbin
    Quote Originally Posted by Thanhlongbin
    Dear all beginners!
    I've got a simple design for Square Wave Generator with 2 output signals which are time/phase delayed (shifted) each by other.
    Please give description for this design and estimate the period and delay time values.
    Is it a quiz or assignment, at least it is clear now that it is intended to keep beginners busy. As I could understan the wording what best description of the circuit I could give is:
    1. It is an interesting circuit.
    2. Perfect delay is what is offered by the RC circuit.
    Hope this meets your pupose
    (I am a beginner)



  7. #7
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    calculate delay times square wave

    Dear Ark5230,
    Your ans is quite right. This is a simple RC circuit application.
    Let RC=1ms, why do not you give more detail explaination for:
    1. Oscillation frequency value ?
    2. Time(phase) delay between 2 output signal?
    3. Wave form compairision ?



  8. #8
    LvW
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    squarewave delay

    May I suggest to use this circuit for some additional investigations ?

    1.) Of course, no "real" square wave is possible. But which property of the circuit determines the rise and fall times ?
    2.) Can these times be altered ? How ?
    3.) Is there something like hysteresis within the circuit ? Why ?

    --------------------

    In addition, I would like to call this circuit NOT "oscillator". Instead, I would prefer "squarewave generator". Why ?
    A clear and unequivocal wording is important when engineers communicate.
    And I think the word "oscillator" is reserved (or should be !) for linear circuits which are oscillating according to the Barkhausen criterion (unity loop gain) thereby producing a sinusoidal wave.
    (By the way, it´s interesting that each "linear" oscillator must incorporate a non-linear part in order to be able to remain linear. Sounds a bit contradictory, does it not ? A good reason for beginners to think about it)
    Regards
    LvW



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    long duration square wave generator

    Hi LvM,
    @ cmt#1 &2: Let's simplify this "problem" b'cause it intents to beginners only. With LM324 working about some Khz, some hundreds nano second time (propagation, slew rate,..) can be ignored. Squarewave is acceptable.
    @cmt #3: hysteresis is interesting point in this design. Let's it opened for discussing.
    -------------------------------------------

    My english vocabulary and terminology is far to good. I wish I'd learned in Oxford!.
    However, I try to explain some comment for your discussion on the term "Oscillator" and "Generator".
    I think some circuit is called Oscillator if it can make by itself a changing in time signal. We say it oscillates or vibrates. My old teacher used to call it "Multivibrator" only. The signal value (voltage/current) changing must be in a certain range and time duration and it's usually presented in a wave form drawing. The wave form may be square, sawtooth, sinusoidal,.. but never constant.
    I use the term "Generator" for the circuit/device with similar oscillation feature only when it can drive some load without changing it's signal waveform.
    Once time, I need a high accuracy external clock for a MCU to replace the low accuracy passive quartz variant. The Nippon Electronics Company (NEC) offer me a small chip (4 pins) that generate necessary clock signal when power-up. They call it Quartz Oscillator. They do not know what Barkhausen criterion is.



  10. #10
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    how to design a square wave generator

    Thanhlongbin
    Please use authentic information. What one feels in general could create problems. Your post (rather puzzle) is for beginners. Kindly help me understand what is intended by this post.



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    schematic of the simple square wave oscillator

    For beginner only!
    Please open the picture.
    Look at U1A,R1,R4,R5 and C1.
    R1=10K; R4=1K.
    C1=100nF;R5=10K.
    First Question (or puzzle):
    Estimate the period (or frequency) of this RC Oscillator.



  12. #12
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    square wave generator

    Please edit the figure posted for beginners to understan. If the starting point is ambiguous rest may get distracted, particularly beginners.



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