impulse generator circuit

Discussion in 'The Projects Forum' started by CON_ENG, Feb 10, 2010.

  1. CON_ENG

    Thread Starter Member

    Jul 2, 2008
    26
    0
    Hi every body ,
    i am looking for a circuit that produce impulse signal as a part from my project i search in google and i found this circuit .G1 and G2 are gas discharge tube GDT .it is my first time to use this component and i'd like to know is this from 2-pole type or 3-pole. and if it was 2-pole why it's symbol had 3 point? i'd like to know how this work ?and if you had any limitations for using this circuit please, inform me.and if you had any other circuit can do the same function i'd be grateful
    Regards ​
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    It would be helpful to know the application of this circuit. Without an isolation transformer, the circuit is inherently unsafe to use at all.
     
  3. CON_ENG

    Thread Starter Member

    Jul 2, 2008
    26
    0
    i know that but i'll perform this circuit at a low level of voltage so i'll not need it or it will be not neccessary.
    now i need to now the type of gas discharge tube, and certainly thanks.
     
  4. JDT

    Well-Known Member

    Feb 12, 2009
    658
    85
    The black dot in the symbol signifies that the tube is filled with gas.

    These tubes change from insulating to low resistance at the voltages shown. They return to an insulating state when the current falls to some low value.

    So in this circuit C3 charges up slowly through R3 and R4. When a voltage is reached, it will discharge quickly through G1 causing a cascade discharge through G2.

    The circuit is not polarity sensitive so, depending on which button is pressed, pulses of either polarity can be produced.

    Low voltage operation not possible! Take care!
     
  5. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,553
    224
    Gas discharge tubes trigger in the 90VDC to 120VDC range, so the circuit can't be used with "a low level of voltage".

    Ken
     
  6. CON_ENG

    Thread Starter Member

    Jul 2, 2008
    26
    0
    -so, the gas discharge tube used is from 2-pole type.
    -i mean by low value of voltage is 500v value . i know that this circuit is not safe .
    but i need a circuit that generate impulse signal and this is the avaliable one.
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
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    281
    The circuit is simply a fatal accident waiting to happen.

    Can you give any details about the pulse itself? What does it do and what are the necessary characteristics? There is probably a safe way to make your pulse.
     
  8. bertus

    Administrator

    Apr 5, 2008
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    Last edited: Mar 15, 2014
  9. CON_ENG

    Thread Starter Member

    Jul 2, 2008
    26
    0
    ok i need to generate an impulse signal such like lightning strikes but certainly not have the same value i need it as apart from my graduation poroject "lightning and surge protection in photovoltaic installations" so i don't had speciall characteristics except that i need it had an effective value with avery short duration .
     
  10. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    That gives no useful parameters, like voltage and duration. You might think of using an ignition coil to make a high voltage. There is no connection to the power line, so you have a greater degree of safety involved, plus a greater voltage - http://www.madteddy.com/igncoil.htm
     
  11. CON_ENG

    Thread Starter Member

    Jul 2, 2008
    26
    0
    ok i read about igination coils i though it's will be more practical and safe as you told before so i'll choose one of them appropriate to my work instead of the circuit i found .

    Thanks for being cooperative members
     
  12. Wendy

    Moderator

    Mar 24, 2008
    20,732
    2,491
    Would a xenon flash tube transformer work? It generates a 4KV pulse from relatively low voltage, and is pretty common.
     
  13. CON_ENG

    Thread Starter Member

    Jul 2, 2008
    26
    0
    of course thanks for helping
    but i think it's not what i exactly need an igination coil will provide what i need with safty operation and it's easy for me to get it .

    Best regards
     
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