Using a digital multimeter

Discussion in 'General Electronics Chat' started by Then along came a dummy, Jul 27, 2005.

  1. Then along came a dummy

    Thread Starter New Member

    Jun 24, 2005
    Hi guys,

    Don't flame me for this one but i need your opinion on whether my digital mulimeter is broken or if i'm not using it correctly. I am still new at this and am trying to learn electronics on my free time.

    I have a digital multimeter from a buddy (He wasn't interested in electronics). It is not auto ranging.

    For a 100,000 ohm resistor (5% tolerance) i set the range to 200k and tough the leads. I use alligator clips for this. The reading is 98.7. This means the resistor is actually 98,7000 ohms right? That is to say i am to take the reading on the screen and set it to the thousandth place right?

    I also tried to measure the resistance between my hands by holding the meter leads in each hand. The display indicated a "1" until i ranged the meter on the 2M range which ten listed 1.719. Isn't this kind of strange? The range below the 2M range is 200k and below that it is 20k. So could it really be possible that my resistance would be above the 200k range? Do you think the reading is accurate?

    Again, my experience is too limited to be sure, but i would think that resistance between my hands would be around 10k to 20k right? Why did i have to range it to 2M before i registered a reading?

    Thanks to anyone who can help me on this.

  2. pebe

    AAC Fanatic!

    Oct 11, 2004
    Your measurement of resistance and interpretation of the meter readings is correct. Your meter is known as a three and a half digit meter. that means you can get 3 digits which go from 0 to 9 and a fourth (the most significant digit) which can be either a '0' or a '1'. Plus, of course, the decimal point which is put in its appropriate place.

    The maximum reading is therefore 1999. Your 98.7K resistor on the 200K range would measure 098.7 but the leading '0' is suppressed, as is usual to avoid confusion.

    When you measured the resistance betwen your two hands, the '1' on its own indicated that the resistance was above the range being measured. Indeed, 1.97M is higher than 200K. What reading you get will depend on how dry your skin is at any particular time, so don't give too much importance to the readings. To prove a point, damp your skin and you will probably see the resistance go lower.

    Have fun learning. Electronics is all interesting stuff!
  3. w3n6

    New Member

    Mar 9, 2005
    Your measurement on the resistor is correct. We have this what we call the minimum and maximum tolerance of the resistors. It canbe determined by its color code. :) I hope I'm right. :)