Use of a multimeter to identify whether AC or DC voltage is present
How to use a multimeter to quickly distinguish between the power supply is DC or AC, in general, we intuitively be able to determine a general, for example, batteries are generally DC, and the home of the electrical outlet on the electricity is generally AC, but the home if there is a plug in the socket power supply, if the power tag off, this time to consider how to identify the power supply is an AC power supply or DC power supply.
With a power pen is able to easily identify, if this article directly say with a power pen to identify itself does not make much sense, or to share a little technical content with a multimeter to identify the power supply is DC or AC.
For AC power is not distinguishable from the positive and negative poles, with the multimeter AC file to measure in fact positive to measure the opposite measurement results are the same, but DC power with a multimeter DC voltage file to measure the time in fact is not the case, positive to measure the side of the opposite will be a difference of a "-" sign, from which you can distinguish between AC or DC, but there is also a But there is still a problem, that is, in order to use the multimeter to measure the results, in fact, still need to know whether the power supply is DC or AC in order to do so, otherwise the wrong gear and can not show the results.
So it is necessary to come up with another method, assuming that we want to distinguish between the power supply is AC, the multimeter to choose a range of larger
Table to choose a range of AC gear, the black pen to make a bend, about three circles, the black pen hanging in the air, it is best not to touch the black pen with the hands of the table head, for AC voltage gear, touch the black pen and no danger, but for the wrong choice into the AC gear, if not accidentally touched the black pen, and the red pen is in the socket, then it is very dangerous, so in order to be safe! For safety reasons, it is better not to touch the meter pen with your hand.
The next step is to insert the black pen into any one of the power supply jacks, if it is AC, you will find that one of the two electrodes in the power supply jack is able to display the number, if this situation shows that the power supply is AC, otherwise the power supply is DC.
The following picture is the actual picture of the test AC, from the picture can also be seen in the multimeter display does not appear digital.
How to use a multimeter to quickly distinguish the power supply is AC or DC?
But when the meter needle replacement inserted into the position of the power jack, in the display will be able to show the number, if you can show the number shows that the power supply is AC power supply, for DC power supply no matter how you insert, but where inserted into a meter needle actually will not have a voltage.
