crystal with 555

Discussion in 'The Projects Forum' started by king40, Jul 23, 2013.

  1. king40

    Thread Starter Member

    Jul 17, 2013
    75
    0
    hi
    i have a question
    if anybody have information please help me
    this is possible to add crystal for 555???
    or how can increase 555 speed??????:rolleyes::cool:
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,421
    3,356
    What crystal?
    Why do you want to add a crystal?
    Increase 555 to what speed?
     
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  3. shortbus

    AAC Fanatic!

    Sep 30, 2009
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  4. king40

    Thread Starter Member

    Jul 17, 2013
    75
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    i use of 555 for convert voltage to frequancyyyy
    i want increase speed for convert voltage to frequancy
    :cool:
     
  5. wayneh

    Expert

    Sep 9, 2010
    12,093
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    From what to what? Schematic?
     
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  6. king40

    Thread Starter Member

    Jul 17, 2013
    75
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    thanks.but lm2917 convert frequency to voltage not voltage to frequency
     
  7. king40

    Thread Starter Member

    Jul 17, 2013
    75
    0
    voltage to frequency
    with 555
    Schematic:
    [​IMG]
    this is work
    but i think frequency output have delay :(
    and if possible i want increase speed for convert
     
  8. Wendy

    Moderator

    Mar 24, 2008
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  9. LDC3

    Active Member

    Apr 27, 2013
    920
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    This schematic produces an output train of pulses at the same frequency, the only thing changing is the width of the pulses. The input on pin 2 (I assume this is where you want your crystal) retriggers the 555 at a set frequency. The RC network on pins 6 & 7, along with the voltage on pin 5, determine the duty cycle of the output on pin 3. I'm not sure what tw refers to, but I am guessing that it is the time the signal is high.

    BTW, I don't know how to decrease the propagation delay inherent to the chips.
     
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  10. wayneh

    Expert

    Sep 9, 2010
    12,093
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    Any delay is so small that most folks don't worry about it. Changing the control voltage will change the output of the 555 within one clock cycle.

    Define your needs. Perhaps you need a PLL.
     
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  11. king40

    Thread Starter Member

    Jul 17, 2013
    75
    0
    your means is:
    if i increase control voltage,
    output frequency speed increase?????
     
  12. new voodoo

    New Member

    Jul 25, 2013
    5
    2
    that was going to b my suggestion.
    Obviously its a simple APC-type synth and Ive built maybe a hundred of those in various forms but I dont think I understand exactly what he wants to do either..
    King40: maybe you could clearly and simply state what, exactly, you are trying to achieve both in toto (the overall goal of the circ/device), and in particular (w/the delay Q)?

    Its entirely possible that there is a significant language barrier functioning here..
     
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