True or False: Always test your Voltmeter on a known electrical supply before troubleshooting a circuit.

Testing your voltmeter on a known electrical supply before troubleshooting a circuit is a best practice in electrical work. This step ensures that the voltmeter is functioning properly and providing accurate readings. If the voltmeter is faulty, any readings taken while troubleshooting could lead to incorrect conclusions about the condition of the circuit being tested. By verifying the accuracy of the voltmeter against a known source, you can establish confidence in the tool's capabilities, ensuring that subsequent measurements will be reliable. This practice is important for both safety and effectiveness while diagnosing electrical issues, thereby preventing potential hazards or errors during troubleshooting.