Digital Multimeter DT-830B: User Manual and Reviews

Multimeter DT-830B is a device of Chinese production, which is used by many. Those who constantly deal with electronics can not do without such a technique. This article describes what a DT-830B multimeter is. The instruction with the detailed description of the device allows to use it even for beginners.

There are many models that differ in quality, accuracy and functionality.

The device is designed for the following basic measurements:

• Values of electric current;
• Voltage between 2 points in the electrical circuit;
• Resistance.

In addition, the DT-830B and other similar models can perform many additional operations:

• Call the circuit with a resistance below 50 ohms with audible alarm;
• Test the semiconductor diode for integrity and determine its forward voltage;
• Check semiconductor transistor;
• Measure electrical capacity and inductance;
• Measure the temperature with a thermocouple;
• Determine the frequency of the harmonic signal.

How does the multimeter work?

1. The dial shows the measured values in the form of numbers on a plastic or glass display.
2. The switch provides a change in the functions of the instrument, as well as switching ranges. When not in use, it is set to "Off".
3. Sockets (connectors) in the body for the installation of probes. The main thing, with the inscription COM and negative polarity, has a general purpose. A test lead with a black wire is inserted into it. The next, marked VΩmA, has a positive polarity with a red feeler.
4. Test flexible wires of red and black color with mites.
5. Panel for monitoring transistors.

Multimeter DT-830B: the instruction with the detailed description of modes of measurement

Not everyone understands how to measure the necessary parameters of the device. When using the DT-830B multimeter, the instruction manual should be followed exactly. Otherwise, the device may burn out.

1. Resistance measurement

The function is necessary when you need to conduct wiring in the apartment or find a break in the home network. Not everyone knows how to use a multimeter in this case, but you just need to set the switch in the resistance measurement sector to the appropriate measuring range. The device has a sound signaling that the circuit is closed. If there is no signal, it means that somewhere there is a break or a resistance value of the circuit above 50 ohms.

The range of minimum resistances (up to 200 Ohm) is called a short circuit. If you connect a red and black probe to each other, the device should show a value close to zero.

The Chinese-made DT-830B multimeter has the following features when measuring electrical resistances:

1. High error of indications.
2. When measuring small resistances from readings, it is necessary to subtract the value obtained on the contact of the probes. To do this, they are preliminarily closed. On the other ranges of the sector, the error decreases.

2. How to measure the DC voltage

The device switches to the DCV sector, divided into 5 ranges. The switch is set to a significantly higher range of values. When measuring voltage with battery power of 3 V or 12 V, you can set the sector to "20". A large value should not be set, because the error of the readings will increase, and with a smaller value, the device may burn out. For rough measurements, if the accuracy is only 1 V, the multimeter can be immediately set to "500". Similarly, when the measured voltage is unknown in magnitude. After that, you can gradually switch the range to lower values. The "HV" warning, which lights up in the upper left corner, signals the highest level of measurement. Higher voltages require caution when working with the instrument, although as a voltmeter from the DT-830B multimeter it is safer than an ammeter or an ohmmeter.

Observing the polarity of the probes for a digital instrument is not necessary. If it does not match, this does not affect the amount of readings, and the "-" sign lights up on the left.

3. How to measure AC voltage

The installation in the ACV sector is performed in the same way as in DCV. A high voltage of 220-380 V can cause the device to malfunction due to improper connection.

4. Measuring the value of direct current

Small currents for electronic circuits are measured in the DCA sector. In these switch positions, a voltage measurement is not permissible. In this case, a short circuit will occur.

To measure the current value to 10 A is the third socket, in which the red probe should be rearranged. Indications can be taken in just a few seconds. Usually an electric current is measured by an ammeter. Use the instrument in this case carefully and when measurements are really needed.

5. Check of serviceability of diodes

In the opposite direction on the diode, the device should show infinity (unit on the left). In the forward direction, the voltage at the transition is 400-700 mV.

On this sector, you can also check the serviceability of the transistor. If it is represented as two diode, connected diode, it is necessary to check each transition for breakdown. For this it becomes clear where the base is located. For type pnp it is necessary to find a positive terminal (base) with a positive probe so that the negative probe shows infinity on the other two (emitter and collector). If the transistor is of type npn, the base is a negative probe. To find the emitter, it is necessary to measure the resistance of its transition, which is always greater than the collector resistance. For a serviceable element, it must be in the range of 500-1200 ohms.

By calling the transitions with the multimeter in the forward and reverse directions, you can determine whether the transistor is working or not.

6. Sector hFE

The device can determine the current gain of the h21-transistor. To do this, just insert its 3 pins in the appropriate socket pockets. The display will immediately show "h21". To get the correct results, you need to distinguish the types of pnp (right side of the panel) and npn (left side).

7. The possibilities of improving the device

On the DT-830B multimeter, the instruction provides a certain number of functions. Models differ from each other slightly, and if desired, you can improve any, for example, add capacitor capacitance measurement, temperature and all other additional functions listed earlier.

Description of the multimeter DT-830B in advertising and feedback is quite true.

The basis of the multimeter is an analog-to-digital converter (ADC).

Multimeter DT-830B: schematic and repair

For an inexpensive small-sized device, ICL7106 is most often used.

When measuring voltage, the signal is sent from the switch through the resistor R17 to the input 31 of the chip. When the AC voltage is measured, it is rectified through the diode D1, after which the signal also passes through the chain to the terminal 32 of the microcircuit.

The measured DC produces a voltage drop across the resistors, after which the signal is also applied to the input 32. The chip is protected by a 0.2 A fuse installed at the input.

The device often breaks down due to loss of contacts and incorrect switching. First of all, the fuse is checked and changed.

The device works reliably when measuring voltage, since it is well protected at the input from overloads. Failures can occur when measuring resistance or current.

The burned resistors can be determined visually, and the diodes and transistors can be checked using the methods given earlier. Check for the absence of breaks and the reliability of the contacts.

When repairing the device, the power supply is checked first. Then, the microcircuit is in good working order. It should be operable if the voltage at pin 30 is 3 V, and there is no breakdown between the power supply and the common pin of the chip.

When disassembling, you should not lose the ball of the switch, without which it will not be securely fixed.

When should I change the battery?

The power supply of the device changes in the case of disappearance of the digits on the display and deviation of the measurement results from approximate known values. A picture of the battery appears on the screen. To replace it, remove the back cover, remove the old one and install a new one.

Using the multimeter DT-830B is very convenient: the battery changes easily and very rarely. Just need to work with him very carefully. The device can easily be burned when used incorrectly.

Reviews about the device

About such a device as the digital multimeter DT-830B, reviews are mostly positive. It is unpretentious, multifunctional, and the battery lasts for years. All are satisfied with the low price of the device. Comments appear only on small things.

Styli should be replaced, as they quickly fail. Their resistance is close to the standard one and is 0.5 ohms.

Conclusion

The multimeter DT-830B is a universal device, necessary for the home master and for the professional. It has many important functions and is inexpensive. For successful use it is necessary to study in detail what a DT-830B multimeter is. The operating instructions must be strictly adhered to, so that there are no errors leading to the failure of the device.