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.

 

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 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?