What is the measured voltage of the series-parallel circuit between terminals A and B?

What is the measured voltage of the series-parallel circuit between terminals A and B?

• A. 6.0 volts
• B. 1.5 volts
• C. 3.0 volts
• D. 0 volts

Answer: (C)

In a series-parallel network, the voltage you measure across a part of the circuit depends on how that part sits in the overall path of current. The voltage drops add up across series elements, and a parallel group has the same voltage across all its branches. If the portion between the terminals you’re measuring is a parallel block that’s in series with another resistance, the voltage across that parallel block is a fraction of the total supply given by the ratio of the parallel block’s equivalent resistance to the total resistance in the loop. In this setup, that ratio happens to be 1/2, so the voltage across the measurement points is half of the source voltage. With a 6 V source, that yields 3.0 volts. So the measured voltage between the terminals is 3.0 volts.

In a series-parallel network, the voltage you measure across a part of the circuit depends on how that part sits in the overall path of current. The voltage drops add up across series elements, and a parallel group has the same voltage across all its branches. If the portion between the terminals you’re measuring is a parallel block that’s in series with another resistance, the voltage across that parallel block is a fraction of the total supply given by the ratio of the parallel block’s equivalent resistance to the total resistance in the loop. In this setup, that ratio happens to be 1/2, so the voltage across the measurement points is half of the source voltage. With a 6 V source, that yields 3.0 volts. So the measured voltage between the terminals is 3.0 volts.