Which statement is true about measuring devices in circuits?

Prepare for the Automotive Service Technician Period 1 exam. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

When you measure electrical quantities, you place the device so you’re measuring the intended quantity without unduly altering the circuit. To measure current, the meter must be inserted in the path of the current, so all the current flows through it—that’s a series connection. To measure voltage, you position the meter across the element or branch of interest so it senses the potential difference with minimal current draw; this is why voltmeters are designed with very high input resistance, effectively keeping the circuit in a parallel arrangement with the component being measured. An ohmmeter, on the other hand, applies its own small current to the component to determine resistance, and it’s used on circuits that are de-energized. In real life, voltmeters do load the circuit to some degree because no meter has infinite input resistance, so the notion of “no loading” isn’t strictly true. Among the options, the statement about the voltmeter’s connection best reflects how voltmeters are used to measure voltage across a component, which aligns with practical measurement practice.