What is the correct voltage if the selector is in the 20 DCV position?

When a selector is positioned at 20 DCV, it indicates that the measurement device is configured to read direct current voltage up to a maximum of 20 volts. In this context, we're examining potential voltage levels that could be measured within that range.

The correct answer, which states -17.26 VDC, suggests an understanding of the device's ability to measure not just positive voltages, but also negative voltages. When measuring a DC voltage, it is important to recognize that the polarity of the voltage is relevant. A reading of -17.26 VDC indicates that the measured voltage is 17.26 volts below ground potential, which is well within the capacity of a voltmeter set at 20 DCV.

The significance of this understanding lies in recognizing the importance of polarity in measurements, especially in applications where DC circuits may have components that can operate in both positive and negative voltage ranges. Being trained on such equipment means you can expect to encounter various voltage levels, and knowing how to interpret those readings is crucial for effective troubleshooting and analysis in substation environments.