Multimeter dt 838 download instructions for use. How to use a multimeter - description and operating instructions

Modern measuring devices have long reached a new level - digital technologies have firmly occupied almost all positions, displacing outdated analog devices. To a large extent, this also affected such common measuring instruments as a voltmeter and an ammeter. Now, in a small convenient case, a device fits, which allows you to measure with high accuracy both the main parameters - current strength, resistance, voltage, and many others - frequency, capacitance, temperature, etc.

And this multifunctional device is called a digital multimeter. Why you need it, how to choose and use this device correctly, we will tell further.

How to choose the right multimeter

The most common models of these digital measuring instruments are:

• digital tester DT-830 .. DT-838 and their analogues M-830 - M-838;
• Mastech MY-61 .. MY-68;
• current clamp UT 201 .. UT 207;
• MS-8205;
• DT 9202 .. DT 9208.

Modern digital devices provide a lot of opportunities. The main parameters and measurement modes for all models of these devices are the same - they are all capable of determining voltage, current and resistance.

Each model also includes one or more additional features:

• chain continuity with audible signal,
• diode test,
• definition of inductance,
• capacitor capacitance measurement (models MY-63, MY-65, MY-68, UT-70C, DT-9202A, DT-9208A)
• signal frequency detection (MY-63, My-65, MY-68, DT-830A, DT-832, DT-832H, UT-70C)
• devices with temperature measurement (DT-830BL, DT-837, DT-838, М-838),
• checking and determining the parameters of transistors (models MY-68, MY-65, MY-67, MY-63, DT-182, DT-830B, DT-832, DT-832H, DT-838),
• multimeters with current clamps (MY-68, UT-201/202/204/205/207/208, 266 series instruments).

In addition, there are models of these digital devices with an oscilloscope, an RS-232 connector (communication with a computer), a built-in signal generator, and other unique features.

The choice of a digital meter for the home is determined primarily by the parameters that need to be controlled

Those. It doesn't make sense to buy a professional digital meter with a built-in oscilloscope if you're choosing a device to use in the garage to determine the state of charge of the battery. Devices that measure frequency or transistor parameters are also rarely needed for measurements, unless you are doing it professionally.

Therefore, due to their versatility, acceptable parameters, good quality and low cost, testers of the DT-830 .. and Mastech MY-61 .. series are most widely used.

How to choose the right digital meter, the following video will tell you:

How to use these measuring devices

Devices of this type are among those products, the misuse of which in most cases leads to their failure. And given that they are practically unrepairable, then you should work with the device carefully, having studied the instructions and having at least basic knowledge of electrical measurements.

How to use the most common multimeter DT 830B

Working with this model involves the following types of measurements:

• Current measurement: this device allows you to measure only direct current. To do this, the probes included in the “COM” and “VΩmA” sockets are connected to the circuit in series with the load. At a current of more than 0.2 A, the “VΩmA” probe is switched to the “10A” socket. Set the limit switch to the required position.
  For measuring alternating current it is necessary to use the device type DT-9202A/9208A.
  Measurement by the device of current strength over 10A is not provided. For these purposes, use a model with clamp meters, for example, the Mastech MY-68 model.
• Voltage measurement: The device can measure DC and AC voltage values. To do this, the probes are connected to the “COM” and “VΩmA” jacks, and the switch selects the type of voltage DCV - constant, ACV - variable, and the required limit.
  How to determine the polarity of the voltage: When connecting the black probe to the “COM” connector, the red one to “VΩmA”, and the other ends to the “minus” and “plus”, respectively, the readings on the instrument indicator will be without the “-” (minus) sign
• Resistance measurement: the switch is placed in the “Ω” position to the required measurement limit. The DT-830B meter allows you to control this parameter within 200 Ohm - 2MΩ with an accuracy of 1%
• How to use the DT-832, DT-838 and other testers in this series: just like the 830
• Multimeters M-830 .. M-838 are complete analogues of the devices described above. In addition, M 838 is equipped with a thermocouple for measuring temperatures in the range of 20 .. 300 degrees C

Digital multimeter DT-838 is a good option for home use. It has small size, high reliability and simple design.

Device features

The DT-838 multimeter (or tester, as it is popularly called) allows you to perform a number of measurements:

• Definition of alternating current.

• DC current measurement.

• Determination of current strength.

• Resistance measurement.

• Temperature detection (requires an additional sensor, which is purchased separately).

• Carry out a sound continuity of wires.

The device operates in a wide temperature range (from 0 to plus 40 degrees). Multimeter DT-838 reflects the results of measurements on a liquid crystal display. Moreover, the device measures the indicators not once, but several times. From 3-4 readings, the device calculates the average value, which is reflected on the indicator.

The multimeter is powered by a 9-volt battery. It is included in the delivery set (most often it is already installed in the device). When determining voltage or current, the device is able to automatically determine the polarity. They are recommended to follow. If the polarities are reversed, the value will be displayed with a minus sign.

In addition to the battery, the kit includes:

• Tester.

• Thermocouple.

• Styli.

When measuring, it is very important to connect the probes correctly. To determine the current strength, the probes are connected in series with the load. To determine other parameters, the probes are connected in series.

Working with the device

The DT-838 multimeter is easy to use. But there are situations when, after purchasing the device, people do not know how to use it. There is nothing complicated here.

The range switch is set to the desired mode. To do this, you need to choose one of the given values. The switch itself can be rotated in both directions (both clockwise and counterclockwise). One of the probes is always in the "COM" hole. For direct current, this should be "minus". The second probe is always installed in the VOMA hole. An exception is the determination of the current strength.

Voltage detection

To carry out any measurement, first you need to turn the switch that the DT-838 multimeter is equipped with to the desired mode. The instruction will help you understand which designation corresponds to the required mode.

When choosing the desired mode, you must remember that D.C. in batteries, accumulators, power supplies. On the device, it is designated DCV and is located on the left. For example, when determining the DC voltage of a battery, it is enough to set the mode to twenty volts.

Alternating current is in sockets. It is designated on the device as "AS".

The red probe must be installed in the 10ADC socket. As a rule, it is the top nest.

Additional features

Multimeter DT-838 allows you to measure temperature. To do this, change the position of the switch to the desired mode. Instead of probes, a thermocouple is connected. The tip of the suspension is connected to the object whose temperature is to be determined. In this case, a thermocouple is needed in order to measure the temperature of an object. Without it, the device will show its internal temperature. It is usually at the same level as the room temperature. This function allows you to control the heating (or overheating) of any radio components, microcircuits.

Calling connections is easy. This is necessary to determine the location of the network break (if the wiring is broken). Another possibility is to determine the resulting short circuit. To start the measurement, turn the switch to the required position. Next, two probes need to touch different ends. If a short circuit happened, a beep will sound.

A multimeter is one of the inexpensive measuring instruments that is used by both professionals and amateurs repairing home wiring and electrical appliances. Without it, any electrician feels like without hands. Previously, three different instruments were required to measure voltage, current, resistance. Now all this can be measured using one universal device. Using a digital multimeter is very easy.

There are two main rules to remember:

• ⚡ where to connect the measuring probes
• ⚡ in what position to set the switch for measuring different values

Multimeter appearance and connectors

On the front of the tester, all the inscriptions are made on English language, and even with the use of abbreviations.

What do these inscriptions mean:

• OFF - the device is turned off (so that the batteries of the device do not run out, set the switch to this position after measurements)
• ACV - variable U measurement
• DCV - constant U measurement
• DCA - DC current measurement
• Ω - resistance measurement
• hFE - measurement of transistor characteristics
• diode icon - continuity or diode test

Switching modes occurs using the central rotary switch. At the very beginning of using the DMM, it is recommended that you immediately mark the pointer mark on the switch with contrasting paint. For example like this:

Most of the failures of the device are just due to the wrong choice of the switch position.

Power is supplied from a battery type krone. By the way, by the connector for connecting the crown, you can indirectly judge whether the tester was assembled in the factory or somewhere in Chinese "cooperatives". With high-quality assembly, the connection occurs through special connectors designed for the crown. In lower quality versions, conventional springs are used.

The multimeter has several connectors for connecting probes and only two probes. Therefore, it is important to correctly connect the probes to measure certain quantities, otherwise you can easily burn the device.

The probes are usually of different colors - red and black. The black probe is connected to the connector labeled COM (translated as “common”). Red probe into the other two connectors. The 10ADC connector is used when it is necessary to measure the current strength from 200mA to 10A. The VΩmA connector is used for all other measurements - voltage, current up to 200mA, resistance, continuity.

The main criticism is caused precisely by the factory probes that come with the device. Almost every second multimeter owner recommends replacing them with better ones. True, at the same time, their cost can be comparable to the cost of the tester itself. In the extreme case, they can be improved by reinforcing the bends in the wires and insulating the probe tips.

If you want high-quality silicone probes with a bunch of tips, then you can order them with free shipping on AliExpress.

Previously, pointer testers were also widely used. Some electricians even prefer them, considering them more reliable. However, it is less convenient for ordinary consumers to use them because of the large error in the measurement scale. In addition, when working with a dial multimeter, it is imperative to guess the polarity of the contacts. For digital, if the poles are not connected correctly, the readings will simply be displayed with a minus sign. This is the normal mode of operation, which will not damage the multimeter.

Basic operation of the multimeter

Voltage measurement

How to use a digital multimeter to measure voltage? To do this, put the switch on the multimeter in the appropriate position. If this is the voltage in the socket at home (alternating voltage), then flip the switch to the ACV position. Insert the probes into the COM and VΩmA connectors.

First of all, check the correct connection of the connectors. If one of them is mistakenly set to contact 10ADC, a short circuit will occur when measuring the voltage.

Start the measurement from the maximum value on the device - 750V. The polarity of the probes does not play any role at all. It is not necessary to touch zero with a black probe, and phase with red. If a much smaller value appears on the screen, and the number “0” is in front of it, this means that for a more accurate measurement, you can switch to another mode, with a smaller voltage level scale that your multimeter allows you to measure.

When measuring DC voltage (for example, electrical wiring in a car), switch to DCV mode.

And also start measurements from the largest scale, gradually lowering the measurement steps. To measure voltage, you need to connect the probes in parallel with the circuit being measured, while holding on to only the insulated part of the probe with your fingers so as not to get energized yourself. If the display shows the voltage value with a minus sign, this means that you have reversed the polarity.

ATTENTION: when measuring voltage, be sure to check that the multimeter scale is set correctly. If you start measuring voltage with the DCA switch on, that is, to measure current, then you can easily create a short circuit directly in your hands!

Some experienced electricians advise holding both probes in one hand when measuring the voltage at the outlet. With poor insulation of the probes and their breakdown, this will allow you to protect yourself to some extent from electric shock.

The multimeter is battery operated (a 9 volt crown is used). If the battery starts to run low, the multimeter begins to shamelessly lie. In the outlet, instead of 220V, all 300 or 100 Volts may seem. Therefore, if the readings of the device start to surprise you, first of all check the power. An indirect sign of battery discharge may be chaotic changes in the readings on the display, even when the probes are not connected to the object being measured.

Current measurement

The device can only measure direct current. The switch must be in the -DCA position.

Be careful! When measuring current, if you do not know approximately what the current strength will be, it is better to start measuring by inserting the probe into the 10ADC connector, otherwise measuring the current more than 200mA at the VΩmA connector, you can easily burn the internal fuse.

Here, the probes, unlike voltage measurements, must be connected in series with the measured object. That is, you will have to break the circuit and then connect the probes to the resulting gap. You can do this in any convenient place (at the beginning, middle, end of the chain).

In order not to constantly hold the probes with your hands, you can use alligator clips to attach.

Be aware that if you mistakenly put the switch in ACV mode (voltage measurement) when measuring current, then with a high probability nothing bad will happen to the device. But if the opposite is true, then the multimeter will fail.

Resistance measurement

To measure the resistance, put the switch in position - Ω.

Choose the desired resistance value, or again start with the largest. If you are measuring resistance on a working device or wire, it is recommended to turn off the power from it (even from a battery). Thus, the measurement data will be more accurate. If, during the measurement, the display shows the value “1, OL”, this means that the device is signaling an overload and the switch must be set to a larger measurement range. If “0” is displayed, then vice versa, reduce the measurement scale.

Most often, a multimeter in resistance mode is used during repair work, to check the performance of household appliances, the health of the windings, and the absence of a short circuit in the circuit.

When measuring resistance, do not touch the bare parts of the probes with your fingers - this will affect the accuracy of the measurements.

dialing

Another mode of operation of the tester that is often used is dialing.

What is it for? For example, in order to find an open in the circuit, or vice versa - to make sure that the circuit is not damaged (checking the integrity of the fuse). Here the level of resistance is no longer important, it is important to understand what is happening with the chain itself - is it whole or not.

It should be noted that there is no sound signal on the DT830B.

For other brands, as a rule, a signal is heard when the circuit resistance is not more than 80 ohms. The dialing mode itself occurs at the position of the pointer - checking the diodes.

With a dial, it is also useful to check the integrity of the probes themselves by closing them with each other. Since with frequent use they may be damaged, especially at the point where the wire enters the probe tube. Before each measurement, make sure that there is no voltage in the area where you will connect the probes for continuity, otherwise you can burn the device or create a short circuit.

The compact measuring multimeter DT 838 is a multifunctional instrument. At the moment, the digital measuring multimeter DT 838 is the most affordable and popular. It is used not only by professionals, but also by amateurs both in our state and in many countries of the world.

It gained its popularity due to its cheapness, reliability, ease of operation, convenience and small dimensions. All these digital devices are manufactured at numerous industrial electrical plants in China, and under different brands.

These brands are unique for different regions of our planet, but all models have the same internal structure and differ only in workmanship and equipment. When buying a DT 838 multimeter, the instructions that come with it will come in handy.

By the way, it fits such popular models as M-830B and DT 832.

The question often arises of how to use the DT 838 multimeter. Basically, this is asked by people who first purchased this miracle of Chinese industry. There is nothing complicated here. The range switch is set to the desired mode by turning it in the desired direction. Moreover, it can be rotated in different directions, clockwise or counterclockwise. The probes are installed as follows. One is always in the COM hole, this is a minus for direct current (although the device is not polarity sensitive and will show a minus sign if the polarity is not correct). The second one is in the VΩmA hole for all modes except current measurement.

To measure the current strength, it is necessary to rearrange the second probe into the third hole marked 10ADC and switch to the appropriate current measurement mode. Digital multimeter DT 838 instruction allows you to use 100 percent. It also details all the steps for carrying out various measurements (moreover, the instructions usually mention the models M-830B, DT 832, DT 838). All characteristics of the device are also indicated there (see table 1), some manufacturers in this document may indicate the circuit of the DT 838 multimeter. As practice shows, this equipment is very reliable in operation.

Its only significant drawback for professionals is its low measurement accuracy. Although for domestic needs this is quite enough. Such a device at home allows you to ring wires, semiconductor diodes, measure the presence of voltage, current, check transistors, large capacitors, measure resistance and temperature.

In addition to measuring direct voltage (DCV), current (DCA), alternating voltage (ACV), this measuring device allows you to measure the resistance of resistors according to direct current, the static current transfer coefficient of the base (though only low-power, semiconductor transistors (hFE)) and measure the temperature (TEMPoC) (this requires a special sensor that can be included or sold separately).

A 3.5-digit LCD is used to display the measurement results. The device can automatically determine the polarity when measuring voltage and current. In one second, three or four measurements take place, of which the average is calculated and displayed on the indicator. This small-sized digital device operates in the temperature range from 0 to 40 C. It is powered by a Soviet Krona battery (9 V). All measurement limits of the Resant DT 838 multimeter are overload protected.

This equipment is based on the principle of double integration of an ICL7106 microcircuit (this is an analog-to-digital converter). The ICL7106 chip is similar to our domestic K572PV5 chip. Such an analog-to-digital converter includes differential inputs that are used for the input signal and for the reference voltage reference.

This design of the microcircuit allows you to measure the voltage, while not being tied to the power source of the microcircuit itself, which allows you to eliminate common-mode interference, both in the signal circuits and in the circuit of the exemplary reference voltage. You can read about the detailed structure of the internal structure, the possible application of this type of microcircuit on the Internet.

The DT 838 multimeter is manufactured according to classical schemes for the type of analog-to-digital converter used, with accurate dividers on resistors for all measuring modes. In case of failure, it is recommended not to repair the device, but to buy a new one, since it is quite cheap.