Electrical/Electronic Systems
Work Example 17

WorkKey Level: 5
NATEF Automotive Tasks:

Problem:

You are helping a buddy install a light bar on his four wheel drive truck, which has a 12-volt battery. It uses four huge spotlights so he can 4 wheel at night. They are hooked up in parallel and use 1 ohm resistance bulbs.

He is continually blowing 30-amp fuses!

Does he have a short or is the fuse too small? Oh yeah? Well—prove it!

1. Calculate total circuit resistance using the attached diagram. ___________

2. Use ohms law to figure the current.__________

3. Determine the problem.

Solution:

1. R_t = 0.25Ω

2. 48 A

3. The fuse is too small.