basic electric theory (series circuit)

Discussion in 'Homework Help' started by xbox112005, Oct 30, 2011.

  1. xbox112005

    Thread Starter New Member

    Oct 30, 2011
    Need help,this is one of 5 questions that I need help with.A circuit. Contains 8 incandescent lamps connected in series across 480v.One lamp has burned out and you must determine which one is defective. You have available. A voltmeter, ammeter, and ohmmeter. Which meter would you use to determine which lamp is defective in the shortest possible time? Explain how you would use this meter and why.
    Last edited by a moderator: Oct 31, 2011
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
    Draw the circuit then ask yourself the following questions:

    1. Is there a current flow in a circuit with 8 resistors in series where of them is interrupted?
    2. Would you use an Ohmmeter in an energized circuit?
    3. What's the resistance of a burnt light bulb (in relationship to the intact ones)?
  3. JDT

    Well-Known Member

    Feb 12, 2009
    3 tests maximum. Use voltmeter if still connected to the supply. Ohmmeter if not.

    A similar technique is used in Analog to Digital converters called Successive Approximation. Also called a Binary Search.

    OK: if you had 16 lamps in series with one blown - how many tests then?