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    Whats the difference between a current short VS a voltage sh

    Whats the difference between a current short VS a voltage short?
    any examples please?

    HOw do you know when your testing a circuit that it has many shorts? but how would you tell "where" they are at?

    Types of Shorts:
    1.) VCC to ground
    2.) component shorts
    3.) AC signal shorts
    4.) 12 volt short ( when using relays or LED's)
    5.) Any other ones please?

    Some shorts raises the current why is that? why does the current raise up?
    What kind of shorts are these?

    Some shorts will Draw more current from the wall wart , what kind of shorts are theses that draw more current from the wall wart power supply?

    How do you know if its a current short or a voltage short?

    I know audio shorts don't harm or draw alot of current or raise the current up , AC signal Shorts don't draw or raise the current up they just kill the signal off

    What other kinds of shorts are there and to test for please?

    •   Alt5th April 2008, 04:06

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    Re: Whats the difference between a current short VS a voltag

    Quote Originally Posted by walters
    HOw do you know when your testing a circuit that it has many shorts? but how would you tell "where" they are at?
    If there were easy answers to these questions a lot of engineers would spend much less time behind benches faultfinding equipment. I would have a lot less grey hair also. Using a Huntron instrument and experience makes life a lot easier.



    •   Alt5th April 2008, 05:59

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    Re: Whats the difference between a current short VS a voltag

    At short is a connection of two nets that should not be connected, but I don't know what a voltage short should be in contrast to a current short. That's no usual technical term to my opinion.

    From a practical viewpoint, you may find some differences of the kind you listed, e. g. if a short causes immediate damage of other circuit parts, could be beared for some amount of time or infinitely.

    Single shorts on a PCB usually can be locates by applying a current limited low voltage and tracing the voltage drop.



    •   Alt5th April 2008, 16:39

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    Re: Whats the difference between a current short VS a voltag

    1.) What is a Huntron instrument ? and what does it do?


    2.) applying a current limited low voltage and tracing the voltage drop

    What can i use to do current limitting?

    Tracing the voltage drop? how would i know which voltage drop is bad ? can u please explain more?

    Can i use a protection diode to help out also? but a diode between the wall wart power supply and the PCB circuit ?

    Added after 8 minutes:

    There are only 3 types of shorts:

    1) Short to Vcc
    2) Short to GND
    3) Pin to pin short
    Types of Shorts:
    1.) VCC to ground
    2.) component shorts
    3.) AC signal shorts
    4.) 12 volt short ( when using relays or LED's)

    Current short or a voltage short

    shorted a current source to a potential
    A short is a (usually non-intentional and unwanted) conductive path.
    A conductor can drop onto a circuit board and make a path. Bad soldering can short two adjacent pins on an IC together

    Any other examples of shorts from your experience or knowledge please??



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    Re: Whats the difference between a current short VS a voltag

    http://www.huntron.com/products/diagnostics.htm

    Helps finding faulty nodes including shorts quickly



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    Re: Whats the difference between a current short VS a voltag

    how do you guys find SHORTS ? what are some basic steps to take when finding a bunch of SHORTS?



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    Re: Whats the difference between a current short VS a voltag

    Hi,
    The first principle to handle shorts is to follow the adage ' Prevention is better than Cure'. So,do everything necessary to reduce possibility of shorts at each stage of a product cyle including design stage.
    While making PCB design, try to give sufficient spacing between tracks and component to component. For instance, the discrete resistors have got painted metal cap at their ends and if they are mounted very close to each other the paint may brake off and short each other. For such resistors, it is also advisable to mount it slightly lifted above the PCB so that the cap does not press against a track underneath. Take extra care to physically isolate power dissipating components from other components. Also try to avoid as far as possible vertical mounting of components and use mechanical or other fastening methods to clamp large size components.

    Training of your soldering hands in careful handling of the PCBS is eqally important.

    After taking care in the design and manufacturing stage, introduce visual or automated inspection at each stage of manufacuring. For example, the incoming blank PCB may be subjected to automatic check to weed out 100% of all shorts and open conditions of tracks. Many soldering shorts in the assembled PCB can be easily found out with visual inspection. Also ensure that mounting of all polar componenets like diodes, LEDs, Electrolytic capacotors etc. are 100% visually inspected before powering up.

    If you have socketed components, plug them in only after powering up the assembled PCB once and ensuring all DC voltages on the board are OK.

    I hope these are some of the precautions that you can take to ensure that the harmful shorts are detected and removed before they can cause any serious damage.

    Regards,
    Laktronics



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