3.15 (a) Why is there a measurement error when an ammeter is inserted to measure the current in a branch of a circuit? (b) In the circuit shown in Fig. 3.2, the current flowing between A and B is measured by an ammeter whose internal resistance is 85 Q. The resistance values are given by: R = 3000; R = 2009; R3 = 50092; R4 1500; R5 5000. = What is the measurement error caused by the insertion of the measuring instrument into the circuit? R2 C R4 w E ww R3 Ammeter A Rm Amps R5 B D w R (a) Ammeter R2 C R4 A w Rm R w R3 D (b) B Amps R5 RCD (c) Figure 3.2 0 D A B RAB