How can one determine a current is AC or DC by use of an analog multimeter? Or its workaround with rudimentary tools or equipment ?
2 Answers
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Analog multimeters are normally based around a DC microammeter. Each DC volt range adds a suitable series resistor to limit the current. AC voltage ranges add an extra rectifier.
So try measuring the voltage on an AC range. If in doubt, start at a high voltage and work down. Then switch to the equivalent DC range.
If the meter reads on both AC and DC, it's DC. If it only reads on AC, then it's AC.
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I haven't used analog meters in quite a while, but I kind of recall that they often have a different selector position for DC and AC, at least in volt mode. So that would be one way.
Another way would be to use it in volt mode, and compare a direct reading with one taken with the meter in series with a diode. If the voltage drops by about 1V, you have DC. If the voltage drops by half, you have AC. However, this may not work with small signals or slow AC frequency.
