Question

section 5 - 10 troubleshooting

1. a string of five series resistors is connected across a 12 v battery. zero volts is measured across all of the resistors except (r_2). what is wrong with the circuit? what voltage will be measured across (r_2)?

72 • series circuits
figure 5 - 88

1. by observing the meters in figure 5 - 88, determine the types of failures in the circuits and which components have failed.
2. what current would you measure in figure 5 - 88(b) if only (r_1) were shorted?

Explanation:

Step1: Analyze the circuit issue

Since zero volts are measured across all resistors except $R_2$ in a series - connected circuit with a 12 V battery, $R_2$ is open - circuit. In a series circuit, if one component is open - circuit, no current flows through the rest of the components and thus no voltage is dropped across them.

Step2: Calculate the voltage across $R_2$

In a series circuit with an open - circuit component, the full battery voltage appears across the open - circuit component. So the voltage across $R_2$ is equal to the battery voltage. The battery voltage is 12 V.

Answer:

The problem with the circuit is that $R_2$ is open - circuit. The voltage measured across $R_2$ is 12 V.