How would you differentiate between a short circuit and an open circuit in sensor wiring using measurements?

• A. A short circuit is indicated by very high resistance.
• B. A short circuit shows current flow normally.
• C. An open circuit shows low resistance.
• D. A short shows abnormally low resistance between power rails; an open shows very high or infinite resistance; verify with continuity checks and supply presence.

Answer: (D)

The concept here is how resistance and continuity reveal where current can travel in a circuit. A short circuit creates a path of abnormally low resistance between power rails, so measurements show a very small ohmic value and a continuity test will typically beep, indicating a closed conducting path where it shouldn’t be. An open circuit, on the other hand, breaks the path, so the resistance between the rails is very high or effectively infinite and there is no continuity beep. To verify, measure with the circuit unpowered: check the resistance between the supply and return lines, then perform a continuity check to see if a low-resistance path exists. It’s also useful to confirm the actual supply presence separately, so you know the expected voltage is delivered under normal operation. In short, a short shows abnormally low resistance with continuity; an open shows very high resistance with no continuity.