Voltage tester: rules for using the device when measuring electrical characteristics

In everyday life, situations often arise when it is necessary to measure the voltage in the network or check the wire for breakdown. A voltage tester is used to solve these problems. Modern devices have wide functionality and are called multimeters. However, for a person who is not involved in a professional electrician, a simpler device will suffice.

Types and design features

All testers can be divided into two large groups - analog and digital. They differ in the way they display information. In analogue readings, measurements are read using an arrow pointer. In digital devices, they are displayed as numbers on an LED or liquid crystal display.

Multimeters are equipped with probes, with the help of which the device is connected to the object of measurement. These structural elements are connected to the equipment using wires of different colors, most often black and red, indicating the negative and positive poles, respectively. The same color coding is applied to the jacks located on the front panel.

Recently, digital multimeters have become more and more popular. Some have a rather serious advantage over the switches - you can not observe the polarity of the connection.

If you use an analog type voltage tester and swap the poles, you can bend the arrow. In a similar situation, when measuring characteristics with a digital device, the display will simply show a negative value.

Cheap Chinese multimeters have little functionality. With their help only a few indicators can be measured:

• constant and also alternating voltage up to 1000 V;
• current strength in electrical circuits;
• active resistance.

More expensive devices provide an opportunity to check semiconductor parts, and if there is a thermocouple or thermistor, then the temperature. The first models of multimeters had a very inconvenient system for changing the measurement range. This required inserting the plug into the desired socket. Now everything has changed, since the devices have a packet switch. It is enough to turn the knob to the desired position and you can start working.

Measurement of electrical characteristics

To take measurements, you must connect the probes to the device. After setting the operating mode regulator to the required position, you can start working. All parameters of electrical circuits are checked according to one algorithm.

DC and AC voltage

To check the voltage with a tester, you must first set the switch to DCV or ACV mode - constant and variable, respectively. The maximum measurement limit should also be selected.

If the AC voltage is measured in the 220 V network, then the switch must be set to the 600 V or 750 V position. This will prevent damage to the device.

The probes are installed in the corresponding sockets depending on the polarity. After completing these preparatory steps, you can begin to measure the voltage. The following limits are most often present on testers:

• 200 m - voltage up to 0.2 V can be measured;
• 2000 m - up to 2 V, for example, on batteries;
• 20 - up to 20 V, corresponds to the voltage of the car power supply;
• 200 - maximum 200 V;
• 750 - up to 750 V;
• 1000 - the maximum voltage is 1000 V.

Current strength and resistance

The measurement limit is in the range from 200 Ohm to 2 MΩ. After connecting the probes, the device must be switched to the Ω-ohmmeter mode. To select the measurement limit you should study the marking of the resistor. For example, if 1K5 is indicated on the radio component, then the tester must be set to 2000 Ohm. When the resistance marking cannot be deciphered, then the regulator is set to a lower value. If after the measurement the display shows the number 1, then the limit should be increased until the real resistance value appears.

Almost all models of multimeters allow you to measure the strength of direct current in an electrical circuit. More expensive devices provide the ability to find out the AC indicator.

To carry out measurements on the device, select the desired mode and connect the probes. By connecting them to the network, you can see the value of the required parameter on the display.

Checking semiconductor radio components

Thanks to modern multimeters, it is possible to check the performance of diodes and transistors. Since the diode is capable of passing current only in one direction, the device must be connected correctly. First, you need to put the multimeter in the appropriate operating mode and connect the negative probe to the cell's cathode, and the positive one to the anode.

After that, the display shows the value of the breakdown voltage, on average, ranging from 100 to 800 mV. By changing the polarity of the probes and repeating the measurement process, you can make sure that the element is working. In such a situation, the display should show a value less than 1. If a unit is displayed for any connection, then the diode should be considered faulty.

The transistors are checked in the Ω mode. It should be remembered that this element must be considered as two diodes connected in opposite directions. The measurement algorithm is as follows:

1. The operating mode of the ohmmeter is set.
2. A red probe with a crocodile clip is connected to the base terminal.
3. The black probe must be alternately connected to the emitter and collector.
4. The readings on the display should be similar to the diode test.

If, after changing the connection points of the probes, the display shows a unit, then the radio component is in good order. To fully verify this, you need to check all three transitions. This is how the "n - p - n" type transistor is tested. To work with "p - n - p" elements, you just need to swap the positive and negative probes of the device.

Voltage testers are universal devices that allow you to determine the cause of a malfunction in just a few minutes. It is quite easy to master the operation of such equipment. After carefully reading the instructions, anyone can use an electrical tester, since the cost of this device is low, and it can be easily purchased at any electrical and radio goods.