Nate Core Practice Test

What should the voltage reading be across good open contacts in an energized circuit?

1. 5 volts

2. 12 volts

3. 120 volts

4. 0 volts

The correct answer is: 0 volts

When measuring the voltage across good open contacts in an energized circuit, the expected reading should be 0 volts. Open contacts signify that the circuit is not complete, meaning that no current is flowing through those contacts. As a result, since there is no closed path for current to travel, the potential difference, or voltage, measured between the open contacts would be zero. In a functioning circuit with closed contacts, voltage is present because the circuit allows for current flow; however, with open contacts, this flow is interrupted. Thus, any measure of voltage across contacts that are not in a closed state should logically result in a reading of 0 volts. Other values, such as 5 volts, 12 volts, or 120 volts, would typically indicate a voltage present in a complete circuit or across closed contacts, which is not applicable in this scenario of measuring across open contacts.