PHYS345 Electricity and Electronics

Answer for P3.2

Source substitution leads to the following circuit:

Simplified circuit for P3-2

The current through 900 ohm experiencing 7.0 V is 7.78 mA; thus the current through R2 must be 2.78 mA. Accordingly its resistance must be 1800 ohm.

Answer for E3.6

(Rhot - Rcold)/Rcold = 4.5 for the stated temperature coefficient and temperature increase. Thus the current surge must be 5.5 times the orerating current for this situation.

Answer for E3.12

I1 = 0.75 A

I2 = 0.25 A

Vx = 2.5 V

Last updated Sept. 23, 1998.
Copyright George Watson, Univ. of Delaware, 1998.