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If you were to put both leads on negative and positive terminals on car battery while connected and have the meter on continuity (the one which beeps), what happens and can it fry/ruin the electronics in a car?

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  • \$\begingroup\$ Never use diode test or a resistance mode where you expect an external voltage. But do use Diode test for ground continuity. Continuity uses a high impedance constant current source of < 1mA to measure voltage such as 1 diode drop of 0.6V .This is how it measures. But It should not damage, unless you disconnect the battery and get > 1kV flyback voltage \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jan 21 at 13:29
  • \$\begingroup\$ I did it by mistake and had it connected for less than 2-3 seconds. \$\endgroup\$ – Tisho Jan 21 at 13:32
  • \$\begingroup\$ Calibrate Null probes for 0V, 0 Ohms. Twist together if it helps reduce noise. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jan 21 at 13:52
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    \$\begingroup\$ A car battery is like an elephant that has no intention to move. Your multimeter on continuity is like an ant pushing against one of the elephant's feet trying to get the elephant to move. Your car and battery are like the elephant: they don't even notice that the ant is doing anything. \$\endgroup\$ – Bimpelrekkie Jan 21 at 14:05
  • \$\begingroup\$ Thank you fellas for the responses. My car is experiencing some electrical gremlins and I was worried it was related to this - thankfully it isn’t. \$\endgroup\$ – Tisho Jan 21 at 14:37
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It's unlikely to do the car electronics any harm at all. The car battery can put out hundreds of amps at 12V if it needs to. A weedy little continuity meter will have little effect on it.

But it could well fry the continuity meter if it's poorly designed. A better designed one will just go into overload mode.

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  • \$\begingroup\$ Seen 1/2" steel bar glow red directly across a battery :) suggest people don't try it to find out... \$\endgroup\$ – Solar Mike Jan 21 at 13:21
  • \$\begingroup\$ Don’t care about the multimeter, just the car. That’s why I’m worried. \$\endgroup\$ – Tisho Jan 21 at 13:24
  • \$\begingroup\$ Furthermore, the meter didn’t beep, just showed nothing on the screen (digital meter). It worked afterwards. Would that mean it went to overload mode? \$\endgroup\$ – Tisho Jan 21 at 13:36
  • \$\begingroup\$ @Tisho Yes. The meter itself only uses a small voltage to see if any current flows. You put 12V across the terminals, so it shut itself down. \$\endgroup\$ – Simon B Jan 21 at 13:39
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No decent multimeter should be damaged by a reasonable amount of voltage (ie, not 10kV) on the leads in continuity mode.

When in doubt, you can always check the multimeter manual. Here's a sample manual page, it mentions the maximum allowed voltage in all modes.

enter image description here

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  • \$\begingroup\$ What about the car itself? I don’t care about the multimeter at all. \$\endgroup\$ – Tisho Jan 21 at 13:24
  • \$\begingroup\$ If it's set to measure current, though... \$\endgroup\$ – Scott Seidman Jan 21 at 13:25
  • \$\begingroup\$ No worries, continuity mode delivers just enough current to dimly light a LED... \$\endgroup\$ – bobflux Jan 21 at 13:26
  • \$\begingroup\$ Seidman, it was on continuity - I used it to check my leads and went straight to the battery by mistake. \$\endgroup\$ – Tisho Jan 21 at 13:38

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