Extech Instruments MT310 Instrukcja Użytkownika Pobierz pdf (Strona 2)

P31220 Lab

Using the DMM’s:

You will be using two DMM’s (Digital Multimeters) in this lab. One of these will be used as a

voltmeter, and the other will be used as an ammeter .

 Turn the POWER switch on. Note: These DMM’s automatically turn themselves off after 30

minutes. To reset, turn the power switch OFF, wait five seconds, then turn the meter

back on.

 Plug one probe into the COM (common) port. This probe is

traditionally black. (The electrons don’t care what color it is.)

 Put the “AC/DC” switch on DC. Make sure that the “HOLD” and

“REL” buttons are off.

 If you want to measure voltage or resistance, plug the other probe

(traditionally red) into the port labeled “VΩ”. For currents, use

“mA” or “A”, depending on the size of the currents you want to

measure. You’ll use “mA” in this lab.

 Turn the DMM knob to the setting for what you want to measure.

 Your meter may automatically choose its range. The range shows

the highest value that can be measured. In general, if you have a

choice of ranges (such as 200V, 100V, 20V, 10V, 2V), start with

the highest range and work your way down to the most appropriate

setting. WARNING: Measuring a current that is too high for your

setting will blow the meter’s internal fuse. Don’t do that! Always

start at the highest range and work your way down!

 About the ± sign: If you are measuring voltage or current, the

minus sign appears when the polarity of the non-COM (traditionally red) probe is negative.

 Pay attention to the UNITS on the display. There’s a difference between Ω, kΩ, and MΩ!

 About error: For the purposes of this lab, you may assume that the error of the DMM is no

greater than 2% of the meter’s reading. In reality, each range on the meter has its own

measurement uncertainty. If you need to know about the DMM’s measurement uncertainty in

more detail, please refer to the manufacturer’s data sheet for the DMM or the sheet posted on

the bulletin board in the lab. (Most are Extech Digital Multimeter Model MT310)

Fig. 1: Extech Model

MT310 Digital

Multimeter (DMM)

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Extech Instruments MT310 Instrukcja Użytkownika Strona 2