Measuring Volts, Amps & Ohms: Ways to use a Digital Multimeter
A digital multimeter is used by technicians in the electrical/electronic industries to measure two or more electrical values-principally Voltage (volts), resistance (ohms) and current (amps). This article consists of the ways of using the device efficiently.
A digital multimeter is a standard diagnostic test tool that is used by technicians in the electrical/electronic industries to measure two or more electrical values-principally Voltage (volts), resistance (ohms)and current (amps). Digital multimeters have several advantages like greater accuracy, reliability, and increased impedance due to which they replaced needle based analog meters long ago in the year 1997. Multimeters are small,light weight and battery operated. Many multimeter accessories are available online like analog multimeter, RS pro multimeters, voltmeter, digital voltmeter, CEM digital multimeter. Metrix digital AC/DC multimeter etc but you must compare multimeter price before buying one. Face of a DM typically includes following 4 components-
a) Display: where you can view measurement readouts.
b) Buttons: to select variousfunctions, options vary with models
c) Dial: to select primarymeasurements like ohms, volts, amps
d) Input jacks: where test leads are inserted
Digital multimeters fall in handful of categories-general purpose, standard, advanced, compact and wireless.
Below are mentioned some of the ways explained below;
1. Measuring resistance: First step of it is connecting the multimeter to the circuit. Then you twist the selector knob to set the multimeter to measure resistance. Then you turn off power to the circuit and remove the resistor you want to measure. Touch the tips of the probes to each side of the resistor and read the display, taking care to note the units.
Measuring voltage: Connect the multimeter to a circuit and set the multimeter for the voltage you're measuring. Measure AC voltage by placing the probes across the component and observe polarity when measuring DC voltage or milli voltage and read the display taking care to note the units.
Measuring current: Choose either the terminal marked for measuring 10 amps or the one marked for measuring 300 milliamps (mA), set the multimeter to measure current, turn off power to the circuit, break the circuit, and then turn the power on to read the display, remembering whether you are measuring amps or milliamps.
Testing diodes: To test diodes, first insert the black probe into the common terminal and the red probe into the terminal marked for measuring ohms, volts or diode test. Then use the selector knob to choose the test diode function. Turn off power to the circuit, test forward bias and reverse the probes to test reverse bias. A reading of ‘OL’ or 0 while testing forward bias, and 0 while testing reverse bias indicates that the diode is bad.
A reading of "OL" or 0 while testing forward bias, and 0 while testing reverse bias indicates that the diode is bad.
Each application with a digital multimeter present spotential safety hazards that must be considered while taking electrical measurements. People should hence, before using any electrical test equipment,refer to the user’s manual for proper operating procedures, safety precautions and limits.