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Faizan
Digital multimeters take advantage of Ohm's law and other properties of electricity and magnetism to measure a wide variety of electrical properties in one package. A good multimeter can measure anything from thousandths of a volt to hundreds of volts with stunning precision. They can measure current and voltage in both alternating current (AC) and direct current (DC), determine the capacitance and resistance of a circuit element and show that a electrically conductive path exists between the two leads of the multimeter.
Measuring AC and DC Voltage
Set the dial in the center of the multimeter to either AC or DC voltage mode. AC is denoted by a wavy line above the maximum voltage and DC with a set of straight lines. Note that if you set the dial to 20 volts DC, the multimeter will read "Overload" if you try to measure anything larger than 20V DC. Set the dial accordingly.
Plug the black lead of the multimeter into the "Common" (often abbreviated COM) terminal. Plug the red lead into the voltage terminal (often colored red).
Locate the positive and negative terminals on the circuit element you're trying to measure. Place the red lead on the positive terminal and the black lead on the negative. In other words, wire the multimeter in parallel with the circuit element you wish to measure.
Measuring AC and DC Current
Set the dial in the center of the multimeter to either AC or DC current mode. Note that if you set the dial to 20 amperes DC, the multimeter may blow a fuse if you try to measure anything larger than 20A. Set the dial accordingly.
Plug the black lead into the "Common" terminal. Plug the red lead into the current measuring terminal. Many multimeters have more than one slot because they can measure either low or high current; select the correct one.
Unwire one end of the circuit element you're trying to measure. Place one multimeter lead on the terminal and the other on the wire that used to connect to the circuit element. In other words, wire the multimeter in series with that circuit element.
Measuring Resistance
Set the dial in the center of the multimeter to measure resistance, denoted by a capital omega (Ω). Note that if you set the dial to 20Ω, the multimeter may read zero if you try to measure anything larger than 20Ω. Set the dial accordingly.
Plug the black lead into the "Common" terminal. Plug the red lead into the resistance-measuring terminal, which is often the same as the voltage-measuring terminal.
Remove the circuit element you wish to measure from any voltage or current source.
Place one lead on each terminal of the circuit element. In other words, wire the multimeter in parallel with the element you're trying to measure. The polarity does not matter.
Detecting Connectivity
Set the dial in the center of the multimeter to detect connectivity. The multimeter represents the connectivity function with a design that looks like a stylized representation of a sound wave.
Plug the black lead into the "Common" terminal. Plug the red lead into the connectivity terminal, which is often the same as the voltage and resistance terminals.
Place one lead on part of the circuit and the other lead on another part. The multimeter will beep if an electrically conductive path exists between the two leads.
Measuring AC and DC Voltage
Set the dial in the center of the multimeter to either AC or DC voltage mode. AC is denoted by a wavy line above the maximum voltage and DC with a set of straight lines. Note that if you set the dial to 20 volts DC, the multimeter will read "Overload" if you try to measure anything larger than 20V DC. Set the dial accordingly.
Plug the black lead of the multimeter into the "Common" (often abbreviated COM) terminal. Plug the red lead into the voltage terminal (often colored red).
Locate the positive and negative terminals on the circuit element you're trying to measure. Place the red lead on the positive terminal and the black lead on the negative. In other words, wire the multimeter in parallel with the circuit element you wish to measure.
Measuring AC and DC Current
Set the dial in the center of the multimeter to either AC or DC current mode. Note that if you set the dial to 20 amperes DC, the multimeter may blow a fuse if you try to measure anything larger than 20A. Set the dial accordingly.
Plug the black lead into the "Common" terminal. Plug the red lead into the current measuring terminal. Many multimeters have more than one slot because they can measure either low or high current; select the correct one.
Unwire one end of the circuit element you're trying to measure. Place one multimeter lead on the terminal and the other on the wire that used to connect to the circuit element. In other words, wire the multimeter in series with that circuit element.
Measuring Resistance
Set the dial in the center of the multimeter to measure resistance, denoted by a capital omega (Ω). Note that if you set the dial to 20Ω, the multimeter may read zero if you try to measure anything larger than 20Ω. Set the dial accordingly.
Plug the black lead into the "Common" terminal. Plug the red lead into the resistance-measuring terminal, which is often the same as the voltage-measuring terminal.
Remove the circuit element you wish to measure from any voltage or current source.
Place one lead on each terminal of the circuit element. In other words, wire the multimeter in parallel with the element you're trying to measure. The polarity does not matter.
Detecting Connectivity
Set the dial in the center of the multimeter to detect connectivity. The multimeter represents the connectivity function with a design that looks like a stylized representation of a sound wave.
Plug the black lead into the "Common" terminal. Plug the red lead into the connectivity terminal, which is often the same as the voltage and resistance terminals.
Place one lead on part of the circuit and the other lead on another part. The multimeter will beep if an electrically conductive path exists between the two leads.
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