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I was doing a short and resistance test in my circuit on testpoints. I was testing the output of a voltage regulator.

When I place the + probe on the power and - probe to ground the meter takes time to find the correct range of resistance until it reaches around 200 kohm, when I reverse the probes that is - on the power and + on ground, the resistance measurements is right away shown to around 3 kohm.

What is the reason for the different resistance values and time to read the resistance? Also what is the correct way to measure (I assume black to ground and red to Vdd)?

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You'll be charging the various caps through the multimeter, which explains timing phenomenon.

If you are reversing the probes with red against ground, it likely means you are measuring across anode to cathode of some protection diode, which isn't very meaningful.

Other than that, the value you get literally depends on every single component on the board, so the exact resistance isn't going to be a meaningful value. Though in case it is a couple of hundred ohms or less you have reason to be worried. Less than ~10 ohm would mean a short.

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