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/sci/ - Science & Math

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File: 10 KB, 335x226, multimeter.png [View same] [iqdb] [saucenao] [google]
11162922 No.11162922 [Reply] [Original]

hello, do i destroy a multimeter if i do something like this? And why.

>> No.11163533

>>11162922
Depends on the amperage. Likely, you destroy or blow fuse. Your capabilities are less than fuse rating.

>> No.11163538
File: 97 KB, 413x413, 20190413_062333.jpg [View same] [iqdb] [saucenao] [google]
11163538

>>11162922
You'll blow the fuse because there is no resistance in your circuit. An ammeter, theoretically, has no resistance.

>> No.11163580

>>11163538
>your DMM in current mode is a superconductor and has no resistance!
brainlets are advised to go back to their home board: >>>/b/

The current shunt in any current-measuring device is a very tight tolerance (0.1% or better) milliohm-range resistor, typically something like 10mOhm to 100mOhm, could even be 1mOhm for very high-current measuring applications.

>>11162922
OP for all intents and purposes you do NOT put a current measuring device like a DMM directly across a current source.
EXCEPTION: The current source is *current regulated* and you're testing the accuracy (or the setting) of the current regulator -- which functionally amounts to having a resistance in series with your DMM.

>> No.11163675

>>11163580
you learn something every day~

>> No.11163906

>>11162922
I don't like your backwards colour coding either.

>> No.11164780

>>11163538
An ammmeter works by measuring voltage drop across an internal resistor of a known value. Then I=v/r
The resistance is low because we want to affect the circuit as little as possible
Thus, it's literally the opposite of what you say, by virtue of being an ammmeter, it has internal resistance. It's just really low compared to the rest of the circuit

>> No.11164925

>>11163538
i'd be surprised the dc source here doesn't have internal resistance.