Mixing a jumper wire with parallel resistors


The way the circuit is drawn suggests that all current flows are uniformly in the same direction across the drawing (right to left), which is incorrect; it was likely drawn this way to introduce a little misdirection.

The 4 Ohm and 12 Ohm are effectively in parallel, equivalent to 3 Ohms.

This equivalent 3 Ohm resistance is in series with the 8 Ohm, for an equivalent of 11 Ohms.

The equivalent 11 Ohm resistance is in parallel with the 5 Ohm, which calculates out to 3.4375 Ohms


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Updated on March 18, 2020


  • Headshot25
    Headshot25 over 3 years

    I've been having trouble trying to figure out how to properly get the equivalent resistance of this circuit (and ones similar) it is always an issue for me when there is a jumper wire that doesn't seem like it's only on one wire but multiple.

    I've tried considering that the 4 ohm resistor is useless and working it out as if the 8 and 12 ohm are in series and parallel with the 5 ohm resistor.

    The circuit

  • Floris
    Floris over 5 years
    This is probably the way this problem is intended to be solved. I'm leaving my solution (for the more general case of 5 non-zero resistors) up but this one gets my vote.
  • user45664
    user45664 over 5 years
    Gets my vote too.