Best way to use Digital Multimeter (DMM) learn in 1 reading

What is a digital multimeter (DMM)?

A digital multimeter mostly called DMM is one of the most widely used meters today for the measurement of various electrical quantities. Digital multimeters are so important in any electronics/ electrical laboratory. These are most important for engineers and technicians. It is needed at home, hobbyist, and professional electronics engineer.  Advantages of Digital Multimeter DMM over Analog multimeter

1. A Digital Multimeter is more accurate than an Analog Multimeter s only needs to read the display.
2. A Digital Multimeter is small in size and easy to use.
3. A Digital Multimeter can be used for the measurement of AC/DC Voltage, AC/DC current, and resistance.
4. A Digital Multimeter is low cost and fast measuring instrument.
5. A Digital Multimeter has an audiovisual indication for testing of components and continuity of cables and wires.
6. A Digital Multimeter has an automatic polarity indication.

Front View and connections of Digital Multimeter

The front side of a digital multimeter is normally very simple but attractive The basic digital multimeter will typically have a switch, display, and connections for the test probes s shown in the following image.

The main connection on a typical digital multimeter is given in the image and description below, but obviously, the exact layout and capabilities will be dependent upon the particular test instrument in use. Let’s know the parts of the Digital multimeter the multimeter has the following parts 1. On/ off switch 2. Display 3. Rotary Switch 4. connections Now it’s time to know the function of each part.

1. Main switch:- there is a push to on switch used to on-off the digital multimeter.
2. Display:- The display on a DMM is normally easy to see and read. most have four digits, the first of which can often only be either a 0 or 1, and there will normally be a + / – indication as well. There may also be a few other smaller indicators such as AC / DC etc depending upon the model of DMM
3. Rotary switch:- There is a single main rotary switch to select the type of measurement to be made and asides from this rotary switch there is a marking of various electrical quantities with range.
4. Connections:- There are some main connections for the probes (connector) to connect to the meter, But only two are needed at a time, there may be three or four. Typically these may be:

• Common – it is used for all the measurements and this will take the negative or black lead and probe
• Volts/ohms – this connection is used for most voltage and resistance measurements and will take the positive or red lead and probe.
• Amps and milliamps – this connection is used for the current measurements and will again take the red lead and probe.
• High current – there is often a separate connection for high current measurements. Care must be taken to use this rather than the low current connection if high levels of current are anticipated

Measuring AC Voltage using Digital Multimeter

Step 1: Fix the black probe in the common plug and the red probe in the V/ ohm plug.

Step 2. With the help of the Rotary Selector Switch select the ACV range voltage position. (If you don’t know about the voltage then select high voltage position.)

Step 3: Switch off the Power supply of the device or the circuit which is under measurement.

Step 4: Connect the black and red probes of the meter to the testing points.

Step 5. Switch on the power supply of the device or the circuit.

Step 6. Read the value in digits displayed on the screen. If digit 1 is displayed then it means the selected range is over range.

Measuring DC Voltage using Digital Multimeter

Step 1: Fix the black probe in the common plug and the red probe in the V/ ohm plug.

Step 2. With the help of the Rotary Selector Switch select the DCV range voltage position. (If you don’t know about the voltage then select high voltage position.)

Step 3. Switch off the Power supply of the device or the circuit which is under measurement. (You can measure even supply is on)

Step 4. Connect the black and red probes of the meter to the testing points.

Step 5. Switch on the power supply of the device or the circuit.

Step 6. Read the value in digits displayed on the screen. If digit 1 is displayed then it means the selected range is over range.

DC Current measurement using Digital Multimeter

Step 1: Fix the black probe in the common plug and the red probe in the mAplug.

Step 2: With the help of Rotary Selector Switch select the DCA range current position.

Step 3: Put off the supply power of the device of the circuit.

Step 4. Connect the probe of the meter properly in series with the circuit.

Step 5. Switch on the supply to the circuit and read the value displayed on the screen. Caution:-When checking the current in the 20A range do not touch the probe for more than 30 seconds on the circuit.

AC Current measurement using Digital Multimeter

Step 1: Fit the black probe in the common plug and the red probe in the 20A plug.

Step 2: With the help of Rotary Selector Switch select the ACA 20 A range current position.

Step 3: Put off the supply power of the device of the circuit.

Step 4: Connect the probe of the meter properly in series with the circuit.

Step 5: Switch on the supply to the circuit and read the value displayed on the screen. Caution:-When checking the current in the 20Arange do not touch the probe for more than 30 seconds or the circuit.

Checking continuity in wire/conductor using Digital Multimeter

Step 1: Fix the black probe in the common plug and the red probe in the V/ohm plug.

Step 2: With the help of Rotary Selector Switch select the audio/ diode range position.

Step 3: Connect the probes of the meter to the ends of the component.

Step 4: If you hear a beep there is continuity then OK and if no beep it means faulty. 

Resistance measurement using a digital multimeter

Step 1: Fix the black probe in the common plug and the red probe in the V/ ohm plug.

Step 2. With the help of the Rotary Selector Switch select the Resistance Ohm range position. (If you don’t know about the resistance then select high resistance position.)

Step 3. Switch off the Power supply of the device or the circuit which is under measurement. (You can measure even supply is on)

Step 4. Connect the black and red probes of the meter to the testing points where you are measuring resistance.

Step 5. Switch on the power supply of the device or the circuit.

Step 6. Read the value in digits displayed on the screen. If digit 1 is displayed then it means the selected range is over range.

Troubleshooting of Digital Multimeter

If the meter does not give a reading, or if it doesn’t give a proper reading then maybe its battery drained or its fuse got defuse so you need to replace the battery or fuse.

Step 1. Open the battery cover screw and slide the cover down.

Step 2. Remove the battery and check its voltage. Normally 9V battery is used if its voltage is less then you need to replace it.

Step 3. If its fuse is defused you can replace it by checking its ampere rating.

Step 4. Discard the old battery and replace it with a new battery.

Step 5. Close the cover and screw the cover on.

To read more topics like DC regulated power supply,  Rectifiers, and many more topics you visit the link bellow

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