Drawback of using Resistors wires as Jumpers!!!

Discussion in 'General Electronics Chat' started by Khalid Khattak, Sep 4, 2011.

  1. Khalid Khattak

    Thread Starter New Member

    Aug 2, 2011
    Dear Friends,
    I have a question. Normally we used 1/4 watt resistors. We solder the resistors on the circuit and trim-off the excessive length of wire. Normally i make single-sided PCB and i have to install jumper wires.My question is can we use these trimmed resistors wires as a bridge/jumper in a circuit? Is it a good practice?
  2. steveb

    Senior Member

    Jul 3, 2008
    It depends on the current level, but that's true of traces too. You always need an appropriate conductor for the current.

    It is common practice with surface mount circuit boards to use zero ohms surface mount resistors as jumpers or as place holders to use a nonzero value if needed. There is not much difference between this and your suggestion.

    If you do do this, try to deliberately introduce zero ohms resistor into your design in places that are useful. For example, the output pin on an Opamp is a good place because it provides a place to insert a resistor or current meter if you are debugging a problem. Or, chose places that provide useful testpoints for attaching a scope probe.
  3. Wendy


    Mar 24, 2008
    I do it regularly with no problems. As Steve suggests current is important.

    I also use lead wire for protoboards too. It is just tin coated copper wire, no big deal.
  4. wmodavis

    Distinguished Member

    Oct 23, 2010
    It's done all the time. No Problem.
  5. shortbus

    AAC Fanatic!

    Sep 30, 2009
    It is my understanding that the zero ohm resistor is used in commercial SMD or even through hole boards instead of jumper wires for only one reason. The reason is that the boards are built by automation/robots. It is easier for the robot to place a zero resistor than a piece of wire.
  6. Khalid Khattak

    Thread Starter New Member

    Aug 2, 2011
    Thank You all for your insights:)...
  7. steveb

    Senior Member

    Jul 3, 2008
    That is certainly a good reason.

    In the case of surface mount boards, the need for jumper wires is much rarer than it used to be. Mulitlayer boards and optimizing auto-routers usually allow the traces to be made directly. One can even steal a little spot from a ground or power plane without any harm. But, yes, if a trace jumper is needed, then zero ohm resistors are easier to install by a robot.

    Another reason for using zero ohm resistors for surface mount boards is that it allows a real resistor to be installed later if needed. There are a multitude of reasons why one might want to design this flexibility into the system. Similarly, the NAP (for not a part) or the DNL (for do not load) is a planned open surface mount footprint, put into the design in case you need a real resistor or capacitor there later. Any design I do has a multitude of zero ohms and DNL parts. This practice has saved my head from the chopping block more than once. It has also made me look like a hero when my design could instantly be reconfigured to provide a solution for an unexpected application.
    Last edited: Sep 4, 2011