NJTY T28B Digital Multimeter User Manual

Introducció

This manual provides detailed instructions for the safe and effective use of your NJTY T28B Digital Multimeter. Please read this manual thoroughly before operation and keep it for future reference. The NJTY T28B is a versatile digital multimeter designed for accurate measurement of various electrical parameters, suitable for both professional and DIY electrical tasks.

Informació de seguretat

The Meter conforms to IEC61010-1 CAT III 600V, 1000V CAT II IEC61010 and pollution level II. A Warning identifies conditions and procedures that are dangerous to the user. To prevent possible electrical shock, fire, or personal injury:

• No altereu el Producte i utilitzeu només com s'especifica, o la protecció proporcionada pel Producte es pot veure compromesa.
• No utilitzeu el producte al voltant de gas explosiu, vapor o en damp o ambients humits.
• No utilitzeu el producte amb les cobertes retirades o la caixa oberta. Hazardous voltagL'exposició és possible.
• No apliqueu més del volum nominaltage, entre els terminals o entre cada terminal i terra.
• No utilitzeu cables de prova si estan danyats. Examineu els cables de prova si hi ha aïllament danyat, metall exposat o si apareix l'indicador de desgast. Comproveu la continuïtat del cable de prova.
• Utilitzeu els terminals, la funció i el rang correctes per a les mesures.
• L'interruptor de rang s'ha de col·locar a la posició de rang correcta.
• No es permet que el senyal d'entrada superi el valor límit especificat per evitar descàrregues elèctriques i danys a l'instrument.
• Quan mesureu televisors o canvieu fonts d'alimentació, tingueu en compte que hi pot haver polsos al circuit que poden danyar el circuit.
• Traieu les bateries si el producte no s'utilitza durant un període de temps prolongat o si s'emmagatzema a temperatures superiors a 50 °C.

Símbols de seguretat

Product Familiarization (Overview)

The NJTY T28B Digital Multimeter features a user-friendly design with a clear LCD screen and intuitive controls. Below is an overview of its main components and functions.

1. Llanterna
2. Llum d'indicació d'alarma
3. Sensor NCV
4. Pantalla LCD
5. Canvi de funció i botó de bloqueig
6. Frequency/Duty Cycle /Capacitance ZERO
7. Botó de llanterna i retroil·luminació
8. Interruptor manual/automàtic
9. mA Input Socket (MAX 600mA)
10. 20A Input Socket (MAX 20A)
11. VΩHzC Socket
12. Socket COM

Característiques físiques

Strong Magnet Feature

The multimeter is equipped with a strong magnet on its back, allowing it to be securely attached to metal surfaces for hands-free operation during measurements.

Configuració

Contingut del paquet

Before starting, please ensure all items are present in the package:

• 1x NJTY T28B Digital Multimeter
• 1x Test Leads (Red and Black)
• 1x K-type Thermocouple
• 2x Ceramic Fuse Tubes
• 1x estoig de transport
• 1x Manual d'instruccions (aquest document)
• 4x 1.5V AAA Batteries (Note: Batteries are not included in some packages. Please check your specific product offering.)

Instal·lació de la bateria

The multimeter requires 4x 1.5V AAA batteries (not included in all packages). Follow these steps to install or replace batteries:

1. Apagueu el comptador.
2. Traieu tots els cables de prova de les preses d'entrada.
3. Utilitzeu un tornavís per afluixar els cargols que subjecten la coberta de la bateria o la coberta posterior.
4. Traieu la coberta de la bateria o la tapa posterior.
5. Insert new 4x 1.5V AAA batteries, ensuring correct polarity.
6. Instal·leu la coberta de la bateria o la coberta posterior i premeu els cargols.

Instruccions de funcionament

General Measurement Guidelines

• Check the battery first; if the battery symbol is displayed, the battery needs to be changed.
• The warning signal (triangle with exclamation mark) besides sockets warns of the maximum input voltage i corrent.
• Canvia al rang correcte abans de la mesura.
• The red lead is positive in polarity, the black lead is negative.

Manual and Auto-ranging

The Meter defaults to Auto-range, indicated by 'AUTO' on the display. Short-press the 'RANGE' button to enter Manual range. In Manual Range mode, press 'RANGE' to increment the range. After the highest range, the Meter wraps to the lowest range. Press 'RANGE' for 2 seconds to return to Auto-range mode, where the Meter automatically selects the range with the best resolution.

DC/AC Voltage Mesura

1. Insert the black test lead into the 'COM' port and the red test lead into the 'VΩHzC' port.
2. Switch the rotary knob to the 'mV' or 'V' range. 'DC' signal will be displayed for DC voltage test. Press 'FUNC HOLD' button to switch to AC voltage test ('AC' will be displayed).
3. Connect the test leads to the loaded circuit.

Nota: El voltage above DC1000V or AC750V cannot be measured; otherwise, the instrument may be damaged. In AC/DC 600mV and AC 6V ranges, the Meter may display numbers even with no input. Short-circuit the 'VΩHzC' and 'COM' ports; if the display returns to zero, the meter is normal.

Vol. Sense contactetage (NCV) Detecció

1. Turn the rotary knob to NCV.
2. Gradually approach the NCV probe to the detected point.
3. When the meter senses weak AC signals, the yellow indicator lights up and beeps slowly. For strong AC signals, the red indicator lights up and beeps quickly.

Note: Do not rely solely on non-contact voltage detectors to determine voltage presence, as factors like socket depth or insulation thickness can affect readings. Induced voltage or external interference (flashlights, motors) may trigger false positives.

Current Measurement (DC/AC)

1. Insert the black test lead into the 'COM' port. For currents under 600mA, insert the red test lead into the 'mA' port. For currents between 600mA and 20A, insert the red test lead into the '20A' port.
2. Switch the rotary knob to the 'A' or 'mA' range. 'DC' signal will be displayed for DC current test. Press 'FUNC HOLD' to switch to AC current test ('AC' will be displayed).
3. Disconnect the circuit to be tested. Connect the black test lead to the lower voltage end of the disconnected circuit and the red test lead to the higher voltagi final. A continuació, connecteu els cables de prova al circuit carregat.

Note: 'OL' indicates overload; switch to a higher range. Do not attempt current measurement if the voltage between the open circuit and ground exceeds 250V. Ensure the fuse is intact. Turn off power to the circuit before connecting the multimeter. Exercise caution with high voltage per evitar descàrregues elèctriques.

Mesura de Resistència

1. Insert the black test lead into the 'COM' port and the red test lead into the 'VΩHzC' port.
2. Switch the rotary knob to the 'Ω' range.
3. Connecteu els cables de prova a la resistència a provar.

Note: 'OL' means overload or open circuit. If the tested resistor > 60MΩ, it may take a few seconds to read. Before testing, ensure the circuit is powered off and high-voltage capacitors are discharged. For low resistance, short-circuit test leads, read their resistance, and subtract this value from the measured resistance.

Mesura de díodes

1. Insert the black test lead into the 'COM' port and the red test lead into the 'VΩHzC' port.
2. Switch the rotary knob to the diode symbol and press 'FUNC HOLD' button twice. ('+' will be displayed).
3. Touch the diode anode with the red probe and the cathode with the black probe.

Note: 'OL' will be displayed if open-circuited or if test leads are connected in reverse polarity. A normal diode in circuit will show a forward voltage drop of 0.5V to 0.8V.

Mesura de continuïtat

1. Insert the black test lead into the 'COM' port and the red test lead into the 'VΩHzC' port.
2. Switch the rotary knob to the continuity symbol and press 'FUNC HOLD' button. ('♪' will be displayed).
3. Contact the probes to the measured circuit or resistance.
4. The Meter will buzz and the indicator light will be yellow if resistance is less than 40Ω. If resistance is >40Ω and <60Ω, the buzzer will not ring, and the indicator light will be red.

Note: Before continuity testing, ensure the circuit is powered off and high-voltagEls condensadors es descarreguen.

Mesura de la capacitat

1. Insert the black test lead into the 'COM' port and the red test lead into the 'VΩHzC' port.
2. Switch the rotary knob to the capacitance symbol.
3. Connecteu els cables de prova al circuit a provar.

Note: Before testing, ensure the circuit is powered off and high-voltage capacitors are discharged. Large capacitance values may take time to stabilize. Observe polarity for correct connection.

Frequency/Duty Cycle Measurement

1. Insert the black test lead into the 'COM' port and the red test lead into the 'VΩHzC' port.
2. Switch the rotary knob to 'Hz%' and use the 'Hz/%/A' button to toggle between Frequency or Duty Ratio.
3. Connecteu els cables de prova al circuit a provar.

Note: Do not test any voltage higher than 250V to prevent electric shock or damage.

Mesura de la temperatura

1. Turn the rotary knob to '°C'. The meter will display the ambient temperature.
2. Switch between '°C' or '°F' by pressing the 'FUNC HOLD' button.
3. Insert the thermocouple into the instrument: positive (red) into 'VΩHzC' input, negative (black) into 'COM' input.
4. Contact the measured object with the thermocouple probe.

Note: When measuring temperature with thermocouples, the probe should not touch charged objects to avoid damage or electric shock.

Backlight and Flashlight Function

• Press the 'light bulb' button to toggle the backlight on and off.
• Press and hold the 'light bulb' button for 2 seconds to turn on the flashlight and backlight simultaneously. Press again to turn them off.
• The backlight and flashlight automatically turn off after 30 seconds.

Retenció de dades

In Display HOLD mode, the Meter freezes the display and 'H' shows on the display. Press the 'FUNC HOLD' button for 2 seconds to activate/deactivate Display HOLD. To avoid electric shock, when Display HOLD is activated, be aware that the display will not change.

Apagat automàtic

The Auto Power Off function is enabled by default at boot, indicated by the 'APO' symbol. Without any operation for about 15 minutes, the Meter will automatically turn off. Press and hold both 'FUNC HOLD' to turn on the meter; this will cancel the auto power off function.

Manteniment

Neteja

• Apagueu el mesurador i traieu els cables de prova.
• Netegeu el cas amb l'anunciamp drap i detergent suau.
• La brutícia o la humitat als terminals poden afectar les lectures.
• Si hi ha alguna anormalitat, deixeu d'utilitzar el mesurador immediatament.

Canvi de bateria i fusible

Refer to the "Battery Installation" section under Setup for detailed instructions on replacing batteries. For fuse replacement:

• Only use the specified fuse (600mA / 250V, 20A / 250V fast melt fuse) to avoid electric shock or personal injury.
• Turn off and check that the test has been disconnected from the measured circuit before opening the battery cover and replacing the new fuse.

Resolució de problemes

This section addresses common issues and their solutions. Always ensure safety precautions are followed before troubleshooting.

• Meter displays 'OL' (Overload): This indicates that the measured value exceeds the current range. Switch to a higher range. For resistance or diode measurements, 'OL' can also mean an open circuit.
• Lectures inexactes:
  • Comproveu el nivell de la bateria; substituïu-la si és baixa.
  • Ensure test leads are not damaged and have good continuity.
  • Verify correct terminals, function, and range are selected.
  • Clean terminals if dirt or moisture is present.
  • For low resistance measurements, perform a short-circuit test of the leads and subtract their resistance from the reading.
• Meter displays numbers in AC/DC 600mV and AC 6V ranges without input: This is normal. Short-circuit the 'VΩHzC' and 'COM' ports; if the display returns to zero, the meter is functioning correctly.
• Meter does not turn on or turns off unexpectedly:
  • Check battery installation and charge.
  • The auto power off function may have activated after 15 minutes of inactivity. Press and hold 'FUNC HOLD' to restart.
• NCV detection issues: Be aware that external interference (flashlights, motors) or induced voltage can affect NCV readings. Do not rely solely on NCV for voltage presència.

Especificacions

For detailed specifications, you may also refer to the official user manual PDF: NJTY T28B User Manual (PDF)

Vol. ACtagEspecificacions

DC VoltagEspecificacions

Especificacions actuals de CA

Especificacions de corrent continu

Frequency Specifications

Especificacions de capacitat

Especificacions de resistència

Diode / Continuity Specifications

Especificacions de temperatura

Consells per a l'usuari

• Always double-check your range selection before making a measurement to prevent damage to the meter or the circuit.
• Utilize the kickstand for hands-free operation, especially when working on complex circuits.
• The strong magnet feature is useful for attaching the multimeter to metal surfaces, freeing up your hands.
• Remember to use the backlight and flashlight in dimly lit environments for better visibility.
• For temperature measurements, ensure the thermocouple probe does not touch live circuits.

Garantia i Suport

For warranty information and customer support, please refer to the seller's terms and conditions or contact the point of purchase. Keep your purchase receipt as proof of purchase.