Learn about the laboratory

First of all, we will briefly tell you what is on the front panel of the meter and what functions can be used when working with the tester, and after that we will tell you how to measure resistance, current strength and voltage in the network. So, on the front side of the digital multimeter there are the following symbols:

• OFF – the tester has been turned off;
• ACV – alternating voltage;
• DCV – constant voltage;
• DCA – direct current
• Ω is the resistance;
  

  How to use a multimeter – instructions for dummies

You can see the appearance of the electronic tester in front of you:

Maybe you immediately noticed 3 connectors for connecting probes? So here you need to immediately warn that it is necessary to properly connect the claws to the tester before measurements. The black wire is always connected to the labeled COM output. Red according to the status: in order to check the voltage in the network, current strength up to 200 mA or resistance – it is necessary to use the “VΩmA” output, if you need to measure the current value above 200 mA, be sure to insert the red probe into the socket labeled “ 10 ADC”. If you do not take this condition into account and use a “VΩmA” contactor to measure high currents, the multimeter will quickly fail because the fuse will burn!

There are also older instruments – analog or, as they are popularly called, analog multimeters. The model with an arrow is almost not used, because this meter has a higher error, in addition, it is less convenient to measure voltage, resistance and current strength on the width of the arrow.

We will talk more about how to use the most modern digital model of the laboratory further, after examining the step-by-step instructions in the pictures.

Voltage measurement

To independently measure the voltage in the circuit, you must first turn the switch to the desired position. In a network with alternating voltage (for example, in a socket), the switch arrow should be in the ACV position. The probes must be connected to the COM and “VΩmA” jack. Next, determine the approximate voltage range in the network.

If there are difficulties at this stage, it is better to set the switch to the highest value – for example, 750 volts. Moreover, if a lower voltage is displayed on the screen, you can turn the switch to a lower level: 200 or 50 volts. Thus, by reducing the setting to a more suitable setting, you can determine the most accurate value. In a constant voltage network, use a multimeter in the same way. Usually in the latter case it is better to set the switch to around 20V (for example, when repairing an auto electrician).

A very important nuance that you should know is that you connect the tentacles to the circuit in parallel, as shown in the photo:

Here, using this technology, you need to use a multimeter to determine direct and alternating voltage in the electrical circuit. As you can see, there is nothing complicated, the main thing is not to touch the exposed parts of the tentacles with your hands, otherwise you will not be able to avoid electric shock. By the way, as a voltage indicator, you can also  use a screwdriver!

Current measurement

In order to independently measure the strength of the current in a circuit with a multimeter, it is first necessary to determine whether direct or alternating current flows through the wires. Next, you need to know the approximate value in Amperes in order to choose a suitable socket for connecting a black probe – “VΩmA” or “10 A”. We recommend that you initially insert the probe into the connector with a higher current value, and if a smaller value is displayed on the screen, switch the plug to another socket. If you again see that the measured value is less than the set point, you should use a range with a smaller value in Amperes.

We draw your attention to the fact that if you decide to use a multimeter as a meter, you need to connect the tester to the circuit in series, as shown in the photo:

Resistance measurement

Well, the safest thing in terms of multimeter safety would be to use a device to measure the resistance of the circuit elements. In this case, you can set the switch to any range of the “Ω” sector, and then select the appropriate setting for more accurate measurements. A very important point – before using the device to measure resistance, be sure to turn off the power in the circuit, even if it is a regular battery. Otherwise, the tester in ohmmeter mode may show an incorrect value.

Most often, a multimeter measures resistance for do-it-yourself home appliance repair. For example, if the iron is not working, you can measure the resistance of the heating element, which has most likely failed.

By the way, when measuring the resistance in a circuit section with a multimeter, you saw the value “1”, “OL” or “OVER” on the display, then you need to turn the switch to the above range, because at the specified setting, overload occurs. At the same time, if “0” is displayed on the dial, move the tester to a smaller measuring range. Remember this point and it will not be difficult to use a multimeter when measuring resistance!

We use the proverb

If you look closely at the front panel of the tester, you can see some additional functionality that we haven’t talked about yet. Some of them are used only by experienced radio technicians, so there is no reason for home electricity to talk about (after all, it is unlikely to be useful in living conditions). But there is another important test mode that you may use – Connection (in the image below we have indicated its designation). For example, to find zero broken wires in a circuit, you need to ring the wires, and if the circuit is closed, you will hear a sound signal. To do this, simply connect the probes to the two desired points in the circuit.

Again, a very important nuance is that you must definitely turn off the power on the part of the circuit that you are going to shave. For example, if you decide to loop the wiring in the house, during operation, turn off the opening circuit breaker in the switchboard. It is highly not recommended to use a multimeter with the power connected!