If there’s a perfect tool for people continually dealing with electricity, the multimeter is such a tool that both professionals and do-it-yourselfers out to have in their toolbox. The multimeter measures anything that has to do with power and electronics. The device measures the following electrical properties: voltage, resistance, and current. In this guide, we’ll learn how to measure the said electronic properties often checked when performing a test procedure using a digital multimeter. Learning how to use a digital multimeter will make things easier.
Multimeter: The Basics
There are three parts to the multimeter:
- The display is presented typically with four numerical values that are capable of showing a negative symbol. There are available multimeters that have backlighting that provides a better view in dark surroundings.
- The ports are where the tester probes are attached. It has the label COM which stands for ‘common’. The ports are the receiving end of electricity that enters the probes from a particular circuit. One of the probes, the red lead, is inserted into the port that has the mAVΩ label. Insert the black tester here. Other ports bear 10A used when measuring large amounts of the current
Types of probes for multimeters:
- IC Hooks – applicable for the legs of smaller ICs
- Test Probes – these are inexpensive and easy to replace
- Tweezers – when SMD parts are getting tested, tweezers give that extra help
- Alligator clips – connects wires to the board. Proves a for a longer time and you get hands-free testing while you focus on the circuit.
How to measure the voltage
- Most electronics are measured using direct current or DC, but we can try testing on an AA battery first to check the voltage. Find the knob labelled with a V and a straight line and set it there. Then connect the probes to the proper ports. Attach the black probe to the COM port and so the same with the red probe to the port with mAVΩ. Connect each probe to the ends of the battery, the terminals at positive and negative. Make sure to insert both probes into the correct port. A new battery should yield about 1.5V.
- The next thing to do is to make sure that the circuit has enough power supply. A circuitry that’s supposed to have 5 volts but is higher than 5.5 volts or lower than 4.5 volts is a clear sign to run a diagnostic should be done on the wiring or the connection.
- For multimeters that have no auto-ranging feature, you will need to set it yourself to a particular range it is capable of measuring. At the V adjacent to a straight line, turn the dial to 20 volts. It is an appropriate setting for a 12-volt battery. An incorrect reading will display a ‘1’ instead.
How to measure resistance
- Let’s try this on a random resistor. On your multimeter, set it at 20kΩ. Apply light pressure while holding the probes at the points of the resistor and see that it will read 0.00, a 1, or the actual value. It means that the meter is reading a 0.97 with a value of 970Ω or 1kΩ.
- Try using a 200kΩ if the meter suddenly read OL or 1. The multimeter overloaded but not in a dangerous way. It simply needs a bit of adjustment.
- Lower the mode to 2kΩ if displays 0.00 or almost at 0.
How to measure current
- Power the multimeter ON and insert the probes to their respective ports. Multimeters would sometimes have connections that are particular for measuring current. You can also expect an option for measuring higher or lower current flow. In this case, select the correct current measurement.
- Set the knob to current and the range. Make sure to pick the highest range possible for the test subjects. It can be adjusted but selecting an upper range than the anticipated one will prevent the multimeter from overloading.
- Increase the range of the best reading. If it’s possible to set the last digits, do not read zero at all, do it to get the most significant numbers.
- After a successful reading, shift the range to the highest voltage when the probes after inserting at the sockets for measurement. This safety measure is to prevent the multimeter from acquiring damage is the probes were connected suddenly without checking the range.