How to use a multimeter for "dummies"? How to ring the wires with a multimeter

A multimeter is a tool for measuring electricity, the same as a ruler for determining distance, a stopwatch for time or a scale for weight. Its difference lies in the fact that it is multifunctional, that is, it can measure different quantities. Most multimeters have a switch that allows you to select what you want to measure.

What does the instrument measure?

Multimeters are capable of measuring current, resistance and voltage, as well as controlling the continuity of the circuit, giving a signal in the event that two things are electrically connected. This is useful, for example, when installing wiring and twisting or soldering wires. A beep indicates that there is a connection and nothing is disconnected. Also, the device can be used to make sure that there is no electrical connection between the two conductors. This will help to detect a short circuit.

You can test diodes with a multimeter. They are similar to a one-way valve that only allows one-way current. Different manufacturers may have different implementations. When working with diodes, if there is no certainty about how it is included in the circuit, or in its serviceability, the possibility of verification will be most welcome. If the tester-multimeter has this function, to find out exactly how it works, you should read the instructions.

More expensive devices can, for example, test the performance and measure the characteristics of capacitors and transistors.

The basics of electrical engineering

Information on how to use the multimeter for dummies. Resistance, voltage, current - parameters that can be measured in units denoted by symbols. For example, the distance is expressed in meters or the symbol m. In electronics, this is:

1. Voltage expresses the force with which electrons are pushed along a circuit. A larger value is equivalent to a greater effort. Measured in volts (V).
2. The current strength expresses how many electrons move along the circuit. A larger value corresponds to a greater consumption of electricity. Measured by amperes (A).
3. Resistance expresses how difficult it is for electrons to go through something. The higher it is, the more difficult it is to pass the current. Expressed in ohms (Ω, omega).

The symbol for the unit of measurement differs from the variable in the equation. For example, Ohm's law is expressed as:

• U = IR, where I is current, U is voltage and R is resistance.

Volts, Amps and Ohms are denoted by V, A, Ω.

To understand how to use the multimeter, for “dummies” it will be useful to bring a simple analogy to help. The current is similar to the movement of water in a pipe. Its greater consumption means more current. The pressure creating the movement of water is tension; higher pressure “pushes” water more, increasing current. Resistance - as an obstacle in the pipe. For example, through a pipe clogged with garbage, water will flow with difficulty. Its resistance will be greater than that of a pipe free of obstacles.

Alternating and direct current

Another information that needs to be learned before using the multimeter. For "dummies" it will be interesting to know that direct current moves in one direction. Its source may be, for example, a conventional battery. Different multimeters differently denote a constant voltage and current. As a rule, these are DCV and DCA, or a straight line over V and A.

Alternating current changes direction many times per second. On a home network, this happens 50 times (in the US, 60 times per second). In different multimeters, alternating voltage and current are indicated in their own way. Typically, ACV and ACA, or a wavy line (~) near or above V and A.

Parallel and serial connection

When using a multimeter, it is necessary to determine the order of its connection, which depends on what needs to be determined. In a serial circuit, the current flowing through each of its elements is the same. Thus, to measure it, it is necessary to connect the device in series. In a parallel circuit, each element has the same voltage. Therefore, to measure it, the multimeter must be connected in parallel.

What do the symbols on the front panel mean?

Another information you need to know before using the multimeter. For "dummies" it will be difficult to understand the many characters on its front panel, especially if there are no inscriptions. No worries. They are represented by units of measure V, A, Ω.

Most multimeters use metric consoles, which behave in relation to units of measure of electricity in the same way as with distance and mass. A meter, for example, is a unit of distance, a kilometer is 1000 m, a millimeter is 1/1000 m. The same applies to kilograms, grams and milligrams of mass. The most common metric consoles used in multimeters:

• μ (micro) = 10 ^-6 ;
• m (milli) = 10 ^-3 ;
• k (kilo) = 10 ³ ;
• M (mega) = 10 ⁶ .

These metric consoles are used for Amps, Volts and Ohms. For example, 200kΩ is two hundred kilo ohms, which corresponds to 200,000 ohms.

Setting limits

Some multimeters are automatically configured, others require manual setting of the measuring range. In the latter case, you should always choose a range slightly higher than the expected value. It is like a ruler and a tape measure. If you need to measure something that is 60 cm in length, then the 50-cm ruler will be too short and you will have to use a tape measure.

The same applies to the multimeter. Suppose you want to measure the battery voltage AA, whose value is expected to be 1.5 V. There are options for 200 mV, 2 V, 20 V, 200 V, 600 V. 200 mV is too small, you need to select the next higher value of 2 V. Even larger the options are too large, their choice would lead to a loss of accuracy (this is how to use a 5-meter tape measure with centimeter divisions without millimeter).

What do other characters mean?

The following symbols are often used in measuring instruments:

1. Wavy line. It is located near the characters V, A, along with metric prefixes. Indicates the variability of the measured value.
2. Solid line, dotted. Located near or above V or A and indicates a constant voltage or current.
3. A series of parallel arcs. Used when checking the electrical connection. How to ring the wires with a multimeter is described below.
4. AC, DC. Instead of lines, the abbreviated name of alternating current (AC) and direct current (DC) current can be used.
5. A triangle with lines drawn through it. Used to test diodes.

Selection options

What should be a good multimeter? User reviews allow you to highlight the following features, which should be paid attention in the first place:

• wires should not be broken after several uses;
• the presence of automatic shutdown;
• convenience of arrangement of buttons and connectors;
• automatic selection of the measuring range;
• large sized LCD screen;
• accuracy class;
• ranges of measurements.

Multimeter: instructions for connecting wires

Measuring instruments are sold together with red and black wires with probes. One end is connected to the multimeter, and the probe is used to test the circuit. The red probe is usually used for positive, and the black for negative values.

Although there are only 2 wires, there are more places to connect them, which can cause confusion. The method of connecting the wire depends on the measurement subject and model, therefore, for clarification, refer to the user manual.

Most multimeters are protected against high current by a fuse that melts and breaks the circuit. This will prevent the device from malfunctioning.

If you attach the probes to an element or section of the circuit, the digital display will show the result. The switch sets the voltage, current or resistance, as well as the measurement limits.

Determining Connection Integrity

How to ring the wires with a multimeter? To do this, you must:

• insert the red wire into the Ω connector, and the black into COM;
• set the switch to the sound signal symbol in the form of parallel arcs;
• connect probes with test points;
• the device will beep if there is a connection between the two probes (i.e., the resistance is close to zero) and will be silent if there is no one.

Multimeter: instructions for measuring resistance

The problem with resistors is that manufacturers want users to remember the color that encodes their characteristics. Here's how to use a multimeter to determine resistance:

• insert the red probe into the Ω socket, and the black into COM;
• connect probes with resistance contacts;
• select the required measurement limit;
• count value.

If your indicator lights 1, then the limit is too small. It is necessary to set the switch to a higher value until a correct reading is obtained. If the value is close to zero, then the limit is too high. It must be reduced to obtain a real indication. If the value is still 0 at the smallest limit, then the measured resistance is zero.

Voltage definition

To measure DC voltage, you must:

• insert the red probe into socket V, and the black into COM;
• connect the red probe to the positive side of the battery or circuit, and the black to negative or ground;
• set the limit switch to the constant voltage measurement position of the expected range;
• read instrument readings.

The maximum current and voltage are indicated on the device next to the sockets. If these values ​​are not observed, the multimeter circuitry may be damaged.

To determine the alternating voltage, you must select the appropriate limit. In this case, the order of connection of the probes does not matter.

Current measurement

• Insert the black wire into the COM connector.
• Insert the red wire into the connector corresponding to the intended measurement range. The 832 multimeter, for example, has connectors for currents up to 200 mA and 20 A.
• Set the limit switch to the DC measurement position of the intended range.
• Read the readings.

Observe the current limitation requirements indicated on the instrument. Otherwise, the fuse will trip if it is installed for a given measuring range or the circuit of the multimeter may be damaged.