What is the first step to take before measuring voltage in a live circuit?

Identifying and understanding the circuit is crucial before measuring voltage in a live circuit for several reasons. It allows the technician to determine the circuit's function, the type of voltage present, potential hazards, and the specific points where the measurement will be taken. By having a clear understanding of the circuit, the technician can also recognize any unusual components or configurations that might introduce risk, helping to ensure a safe measurement process.

This step ensures that the technician is aware of the circuit's voltage levels, current paths, and critical components that may require special consideration, such as capacitors that could store charge or other elements that might cause unexpected voltages. Understanding the circuit also assists in troubleshooting and interpreting measurement results accurately.