If a digital multimeter is set up as shown in figure "B" of the illustration to test an AC solenoid valve coil, what would the display read if the coil is short-circuited? See illustration EL-0214.
• Digital multimeter modes – what the Ω (ohms) position measures versus the AC volts position • Short circuit vs. open circuit – what resistance each condition represents when measuring a coil • How a meter typically displays very low resistance compared to out of limits (OL)
• Look at the meter selector in figure B: is it set to measure resistance or voltage? Which of the answer choices are resistance readings and which are voltage readings? • For a coil that is short-circuited, would you expect its resistance to be very high, very low, or infinite? Which display choice best matches that condition? • When a digital meter is on ohms, how does it usually indicate an open circuit compared to a direct short across the leads?
• Verify what quantity (ohms or volts) the meter is actually set to read in figure B – this rules out some choices immediately. • Decide whether a shorted coil should look more like a piece of wire or a broken wire from the meter’s point of view. • Recall that many meters display “OL” or similar only in one particular situation – confirm which situation that is before picking your answer.
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