Manufacturer of a 12V car headlight

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SUMMARY

The discussion focuses on verifying the current draw of a 12V car headlight, which is specified by the manufacturer to be 6A. Participants calculated the current readings using Ohm's Law (I=V/R) and discussed two scenarios: one with an ammeter measuring 5.71A and another where the fuse would blow due to an estimated current of 120A. The consensus is that the calculations align with theoretical expectations, emphasizing the importance of using Kirchhoff's Laws for accurate analysis.

PREREQUISITES
  • Understanding of Ohm's Law (I=V/R)
  • Familiarity with Kirchhoff's Voltage and Current Laws
  • Basic knowledge of electrical circuits and components
  • Experience with using an ammeter for current measurement
NEXT STEPS
  • Research the application of Kirchhoff's Laws in circuit analysis
  • Learn about the characteristics and limitations of different types of ammeters
  • Explore the implications of fuse ratings in electrical circuits
  • Study the effects of resistance in series and parallel circuits
USEFUL FOR

Electrical engineers, automotive technicians, and students studying circuit theory will benefit from this discussion, particularly those interested in verifying electrical specifications and analyzing circuit behavior.

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Homework Statement


The manufacturer of a 12V car headlight specifies it will draw a current of 6A. You would like to check this claim with an ammeter designed to measure currents up to 10A and having a resistance of 0.1 Ohms.

http://img168.imageshack.us/img168/7831/oaammeterqk3.th.png
What is the current readings in (A) of figure a) and b)


Homework Equations



I=V/R

The Attempt at a Solution


So I think a has a value of 5.71 because 12/(2+.1)...is this wrong...and would figure b) be 0 since the fuse would blow? I'm basically lost.
 
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I think you are right on both. Why do you think you are lost?
 
You did the first part right, which would give the current through the circuit for the ammeter and the headlight (if the manufacturer is right).

In the second part the fuse will probably blow, the current would approximately be 120A, which gives a lot of power. Regardless of whether the fuse flows or not, you ought to figure out the current through there, don't just use my approximation. You can use Kirchoff's Voltage Law or Current Law, or both, with Ohm's law.
 

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