An ideal ammeter is modeled as a short circuit. A more realistic model of an ammeter is a small resistance. Figure P 5.5-10a shows a circuit with an ammeter that measures the current im. In Figure P 5.5-10b, the ammeter is replaced by the model of an ideal ammeter, a short circuit. The ammeter measures imi, the ideal value of im. Ammeter im imi 3 mA 4 k 4 k 2 k im 3 mA 4 k 4 k 4 k 2 k 3 mA 4 k 2 k Rm (a) (b) (c) Figure P 5.5-10 As Rm ! 0, the ammeter becomes an ideal ammeter and im ! imi. When Rm > 0, the ammeter is not ideal and im < imi. The difference between im and imi is a measurement error caused by the fact that the ammeter is not ideal. (a) Determine the value of imi. (b) Express the measurement error that occurs when Rm 20 V as a percentage of imi. (c) Determine the maximum value of Rm required to ensure that the measurement error is smaller than 2 percent of imi. P 5.5-11 Determine values of Rt and isc that cause the circuit shown in Figure P 5.5-11b to be the Norton equivalent circuit of the circuit in Figure P 5.5-11a.

ENGR 121 B Lecture Notes for 9/19/2016 Spencer Kociba Summary of Lecture: beginning to understand the vocabulary and functions in MATLAB and how we will use MATLAB and BlackBoard Learn to turn in assignments, take quizzes, etc. Goal of the course: learn to THINK like a programmer aka step by step problem solving. Problem solving techniques:...