How to use a multimeter correctly
Tips Educational Program / / December 19, 2019
How does the multimeter
As the name implies, the meter serves for measuring a number of electrical quantities. Multifunction instrument combines a voltmeter, ammeter, ohmmeter, continuity, and may also have additional features such as a thermocouple or a low-frequency generator, check the capacitors and transistors.
Analogue testers with scale and arrow almost never occur as long ago supplanted by accessible digital devices. The latter, in addition to the precision and the number of modes differ in the type of a certain value. Automatic show results immediately after selection mode, in the manual further need to expose the measuring range.
All multimeters have a similar structure. The front panel is a screen beneath it is turning the mode dial, and just below - connectors for probes. Some models have a button to turn on the backlight, and storing evidence for other advanced features.
Wires with probes to touch parts in the measurement are connected to the appropriate connectors. Black always carried to the socket with the designation COM, and the red - depending on the magnitude of the current. If it does not exceed 200 mA, to the connector VΩmA, if yes, to 10ADC (10A MAX). In everyday life such high currents do not occur, so it is mainly used VΩmA nest.
The numbers on the scale indicates the maximum value that can be tested in this range. For example, in the mode DCV 20 is measured DC voltage from 0 to 20 V. If it is 21, then you need to switch to one notch above in position 200. It is important to select the range in accordance with the measured, otherwise the meter will deteriorate.
How to measure the DC voltage multimeter
Be sure to connect the probe.
Switch to the constant voltage mode. Usually it is denoted V symbols and dashed straight line or DCV.
The multimeter with manual range additionally set the approximate value of the measurement, but rather a step up. If you are not sure, start with the maximum and gradually decreases.
Tap the contact probes and look at the screen. If the number is displayed, along with a minus sign, then reversed polarity: the red probe concerns minuses, and black - plus.
In manual multimeter, you may have to adjust the measuring range.
If the display unit, it is necessary to increase the limit of measurement, if zero characters OL or OVER - lower.
How to measure the alternating voltage multimeter
Check that the test leads are connected correctly.
Turn on the AC power mode. He marked symbols V ~ or ACV.
The hand-held multimeters also set the estimated value of the measurement. Better one notch above or at the very maximum.
Hold the test leads to the terminals and take a reading from the display.
If multimeter with manual definition of bands and the display unit, increase the measuring range, if zero (OL, OVER) - lower.
How to measure the resistance of a multimeter
Be sure to connect the probe.
Put a resistance measurement mode. It is denoted by the symbol Ω.
If the tester manually, select the approximate measurement range.
Touch probes to the terminals of the resistor and look at the screen of his resistance.
In manual multimeter if necessary, adjust the measuring range upwards or downwards.
As a check diode or chain multimeter
Insert the test leads into the correct connectors multimeter.
Switch to the continuity mode diodes, marked by the arrow symbol with a vertical line.
Attach the needle probe to the terminals of the diode. The meter will show on the screen a voltage drop. If you change the probes in some places, when operating the diode, the screen unit, and on the defective - any other number.
This same mode may be to ring circuit or wire, but must first de-energize them. If the integrity is not broken, you hear a beep if there is an open - the screen simply displays unit, OL or OVER.
On some multimeters audible continuity mode is activated separately. For example, the black tester, as in the photo above. This mode is indicated by a symbol to increase the volume, or note speaker.
How to measure the strength of the current multimeter
Connect the test leads to desired connectors multimeter depending on the current.
Set current measurement mode (DCA, mA).
The multimeter with manual range, set the maximum threshold.
Sequentially connect the probes to the circuit. In contrast to the voltage and current measured resistance is not parallel. That is necessary not just to touch on two points of the circuit or conclusions details, and connect the multimeter in the circuit. When the parallel connection device can be damaged!
The display shows the current consumption of the screen. If the meter manually, you may need to change the range for more accurate results.
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