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For measuring AC current my multimeter has the options:

multimeter options

I just wanted to measure an AC current which I expect to be around 1A. Here are the two measurements I did:

measurement 20A enter image description here

What I always thought was that the 4 sensitivity measuring options for AC currents are meant up to 200μA, 2mA, 20A and 200A ordered increasingly on the multimeter. But why is it showing 9.5 when I select "200" on the meter instead of 1 or something? Before when it was set to 20A it showed me the 0.95A as expected. What is the explanation for that?

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    \$\begingroup\$ What kind of circuit is producing that current? Have you taken the shunt resistors resistance of your meter into account? Have you also properly connected the probes according to the manual necessary for that setting? I have my doubts that you have a 200A setting, its more likely a 200mA setting and you plugged the probes at the wrong place. \$\endgroup\$
    – PlasmaHH
    Commented Sep 8, 2016 at 12:34
  • \$\begingroup\$ @PlasmaHH I think the probes are correct, since my current is around 1A, so that the "mA" jack would be wrong. It's written below that it is for up to 200mA max. It might be some confusion with the order of the options. Aren't they ordered increasingly? It's the current which my door opener takes. \$\endgroup\$
    – Rob
    Commented Sep 8, 2016 at 12:41
  • \$\begingroup\$ read the fine manual, it will tell you that you have a max 20A range and no 200A range. There is no way those probes will do 200A \$\endgroup\$
    – PlasmaHH
    Commented Sep 8, 2016 at 12:56
  • \$\begingroup\$ @PlasmaHH No manual available. The multimeter is 20 years old, approximately. \$\endgroup\$
    – Rob
    Commented Sep 8, 2016 at 13:02

2 Answers 2

Reset to default
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You have to use the 20 A input only with the switch in the 20 A position. The mA input is used with any of the 200 mA, 20 mA, 2 mA and 0,2 mA or 200 µA positions. The setup of the instrument in the right picture is wrong. There is no 200 A range, max. 20 A means no more than 20 A. 200 means 200 mA, not 200 A. You have to read and obey the second and third line from the bottom of the instrument.

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In the 200 setting, shouldn't you have the test lead in the mA socket, not the 20A socket. The 200 is just 200mA, not 200A.

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  • \$\begingroup\$ Are you sure? So the sensitivity options are not ordered increasingly? \$\endgroup\$
    – Rob
    Commented Sep 8, 2016 at 12:46
  • \$\begingroup\$ Yes. If you look at that section of the switch it says AC mA. The numbers without specified units are in mA. The 20A position is also used for 20mA. You choose which scale by moving the test probe. There is no way you would be able to put 200A through that meter with those probes. \$\endgroup\$
    – HandyHowie
    Commented Sep 8, 2016 at 12:53
  • \$\begingroup\$ Ok, yes, that's it, thanks! So the "200" setting is actually not meant to be used in connection with the "20A" jack, right? But what is it showing then? Just still the same, but shifted comma? :-) \$\endgroup\$
    – Rob
    Commented Sep 8, 2016 at 13:01
  • \$\begingroup\$ That is right. By moving the probe you are selecting a different shunt resistor which is only valid on the 20 position. It is displaying the correct digits, but with the decimal point in the wrong place. \$\endgroup\$
    – HandyHowie
    Commented Sep 8, 2016 at 13:06

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