AstroAI DT132A Digital Multimeter

Foreword

Thank you for choosing the AstroAI True RMS 4000 Counts Digital Multimeter.

The AstroAI True RMS 4000 Digital Multimeter is designed for safe and accurate use by professionals in the commercial sector or DIY enthusiasts who require more functionality than a conventional digital multimeter.

This manual contains all safety information, operating instructions, specifications, and maintenance information for the measuring device. This device can perform AC/DC current, AC/DC voltage, resistance, capacitance, frequency, duty cycle, and temperature measurements, as well as diode and continuity tests.

Thank you again for choosing AstroAI. Should you have any questions or concerns regarding your product, please feel free to contact us via support@astroai.com.

Attention

Always adhere to the following rules to avoid electric shock, injury, and potential damage to the measuring device or the devices being tested:

• Inspect the outer casing of the measuring device before use. Do not use the measuring device if it is damaged or if parts of the casing are missing. Check for cracks and missing plastic parts. Pay special attention to the insulation on the connectors.
• Check the test leads for damaged insulation or exposed metal parts. Check the test leads for continuity.
• Do not apply more than the rated voltage indicated on the measuring device between the terminals or between a terminal and ground.
• The manual rotary switch must be set to the correct position before each measurement and must NOT be adjusted during the measurement. Otherwise, the measuring device could be damaged.
• Exercise particular caution when applying the measuring device to an effective voltage exceeding 60 V DC or 30 V RMS AC, as this involves an increased risk of electric shock.
• Always use the correct sockets, functions, and measuring ranges for your measurements.
• Do not use and store the measuring device at high ambient temperatures, high humidity, or near strong magnetic fields. If the measuring device is exposed to moisture, it may affect its functionality.
• Keep your fingers behind the finger guard when handling the test leads.
• Disconnect the circuit from the power source and discharge all high-voltage capacitors before performing resistance, continuity, or diode tests.
• Replace the batteries as soon as the battery indicator appears. Low batteries may lead to incorrect readings, posing a risk of electric shock and injury.
• First, turn off the measuring device and disconnect the test leads from any circuits before opening the casing of the measuring device.
• Use only replacement parts for the maintenance of the measuring device.

Scope of Delivery

• User Manual x1
• Pair of Test Leads x1
• Type-K Thermocouple x1
• AstroAI 4000 Counts Multimeter x1

Figure

The figure below illustrates the components of the AstroAI DT132A Digital Multimeter:

• 1 LCD Display
• 2 Function Buttons
• 3 Rotary Switch
• 4 COM Socket
• 5 A Socket
• 6 Rubber Sleeve
• 7 INPUT Socket
• 8 Test Leads
• 9 Type-K Thermocouple

Dimensions

The dimensions of the AstroAI DT132A Digital Multimeter are:

• Width: 158 mm
• Height: 76 mm
• Depth: 35 mm

Electrical Symbols

Understanding the electrical symbols used on the device and in this manual is crucial:

• DC (Direct Current)
• AC (Alternating Current)
• AC and DC
• °F Temperature in Fahrenheit
• °C Temperature in Celsius
• % Duty Cycle
• Hz Frequency
• ⋎ Capacitance
• •)) Continuity Test
• ➡️ Diode Test
• Ω Resistance
• ⏚ Ground
• ☐☐ Double Insulated
• APO Auto Power Off
• ?️ Freeze Measurement
• MAX Maximum Reading
• MIN Minimum Reading
• AUTO Auto Range Mode
• ➕ Low Battery
• ➖ Negative Reading
• Δ Relative Mode
• ⚠️ Caution: Hazardous voltage may be present
• [FUSE] Fuse
• CE Conforms to EU directives

Function Buttons

Select Button

When setting a multimeter function via the rotary switch, you can select a more specific function using the Select button.

Hold/Backlight Button

Press this button during measurements to freeze the data for easier reading. Press the button again to end the freeze function. Press and hold this button to turn on the LCD backlight. Press and hold the button again to turn off the backlight.

Max/Min Button

• Press this button once during measurements to switch to "Max Mode". In this mode, the multimeter records the measured maximum value. Press this button again to switch to "Min Mode", which records the measured minimum value.
• Press and hold this button to exit "Max-" or "Min Mode".

Relative Button

You can use the Relative button during measurements to obtain more accurate readings by zeroing the resistance of the test leads. To activate this function, simply press the Relative button. A small triangle (Delta symbol) will appear on the display, and the displayed reading should jump to zero. Press the Relative button again to exit Relative Mode.

Range Button

AC/DC voltage, AC/DC current, and resistance can be measured with either automatic or manual range selection. By default, the multimeter is set to Automatic. If you wish to set the measuring range manually, press the Range button repeatedly until you have set the desired range. Ensure you do not select too low a range, as the device may overload and the multimeter will not display a reading. Press and hold the Range button to re-activate automatic range selection.

Hz/Duty Button

When using the multimeter's "Hz/Duty" function, you can quickly switch through the functions by pressing this button. You can also switch to frequency/duty cycle measurement during an AC voltage measurement.

Preparation

1. Connecting the Test Leads: Insert the red test lead into the "Input" socket and the black test lead into the "COM" socket.
2. Function Selection: Turn the rotary switch to the "<0xE2><0x9A><0xAA>" setting and press the "Select" button. Select the continuity mode. The symbol "•))" will then appear on the display.
3. Bring the red and black probes together to ensure they are functioning. The measuring device will emit a loud beep if the test leads are functioning correctly.

Operating Instructions

Voltage Measurement

1. Connecting the Test Leads: Insert the red test lead into the "Input" socket and the black test lead into the "COM" socket.
2. Function Selection: Turn the rotary switch to the "V~" or "V=" setting corresponding to the voltage to be measured.
3. Connecting to the Circuit: Connect one end of the test leads to the circuit to be measured, in parallel with the circuit.
4. Reading the Measurement: Read the measurement value from the LCD display. After the measurement, turn the rotary switch to the "OFF" position to turn off the measuring device.

Note:

• a. For DC voltage measurement, you can determine the polarity of the red test lead connection by the "➖" symbol on the display. If the "➖" symbol is not displayed, the red test lead is connected to positive polarity.
• b. Do not measure voltages greater than 600 V DC or 600 V AC to avoid damaging the measuring device.
• c. Press the Hz/Duty button to switch to frequency or duty cycle measurement during AC voltage measurement.

Current Measurement

1. Connecting the Test Leads: Insert the black test lead into the "COM" socket. If the current is less than 500 mA, insert the red test lead into the "INPUT" socket; if the current is between 500 mA and 10 A, insert the red test lead into the "A" socket.
2. Function Selection: Turn the rotary switch to the "µA=", "mA=", or "A=" settings, depending on the estimated current.
3. Setting Current Type: Press the "Select" button to set the measurement to DC or AC current.
4. Connecting to the Circuit: Connect the test lead in series with the circuit to the source or load to be measured.
5. Reading the Measurement: Read the measurement value from the LCD display. After the measurement, turn the rotary switch to the "OFF" position to turn off the measuring device.

Remarks:

• a. Do NOT measure currents above 10 A DC/AC.
• b. For DC current measurement, you can determine the polarity of the red test lead connection by whether the "➖" symbol is displayed or not. If the "➖" symbol is not displayed, the red test lead is connected to positive polarity.
• c. For high currents, individual measurements should not last longer than 10 seconds for safety reasons. There should be at least 15 minutes between individual measurements.
• d. For current measurements, a load must be present in the circuit. Do NOT connect the multimeter in series with the circuit if there is no load to be measured. Connecting the device in series without a load could damage it.

Resistance Measurement

1. Connecting the Test Leads: Insert the red test lead into the "Input" socket and the black test lead into the "COM" socket.
2. Function Selection: Turn the rotary switch to the "<0xE2><0x9A><0xA5>" setting and press the "Select" button to select the resistance mode.
3. Connecting to the Load: Position the test leads at both ends of the resistance to be measured.
4. Reading the Measurement: Read the measurement value from the LCD display. After the measurement, turn the rotary switch to the "OFF" position to turn off the measuring device.

Remarks:

• a. If the measured resistance exceeds 1 MΩ, the measuring device may take a few seconds to stabilize. This is normal when measuring high resistances.
• b. Do not change the resistance during a measurement. This could damage the measuring device and affect the measurement results.
• c. Do not measure parallel connections. Measurement accuracy will be affected, and results may be inaccurate.
• d. Never directly measure the internal resistance of measuring screws, galvanometers, batteries, and similar devices.
• e. If there is no longer contact, the "OL" symbol will appear on the display.
• f. Before measuring internal resistances of a circuit, please ensure that all power sources are disconnected from the circuit to be measured and all capacitors are fully discharged.

Continuity Test

1. Connecting the Test Leads: Insert the red test lead into the "Input" socket and the black test lead into the "COM" socket.
2. Function Selection: Turn the rotary switch to the "<0xE2><0x9A><0xA5>" setting and press the "Select" button. Select the continuity mode. The symbol "•))" will then appear on the display.
3. Connecting to the Load: Position the test leads at both ends of the load to be measured.

Reading the Measurement: If the circuit load is less than 30 Ω, the buzzer will sound. If it exceeds 30 Ω, the load value will be displayed on the LCD. After the measurement, turn the rotary switch to the "OFF" position to turn off the measuring device.

Diode Test

1. Connecting the Test Leads: Insert the red test lead into the "INPUT" socket and the black test lead into the "COM" socket.
2. Function Selection: Turn the rotary switch to the "<0xE2><0x9A><0xA5>" setting and press the "Select" button to select the diode mode. The symbol "➡️" will then appear on the display.
3. Connecting to the Diode: Connect the red test lead to the positive side of the diode and the black test lead to the negative side of the diode.
4. Reading the Measurement: The measuring device will show the approximate forward voltage. If the test leads are connected incorrectly to the diode's electrodes, "OL" will appear on the LCD. To resolve this, swap the test lead positions. After the measurement, turn the rotary switch to the "OFF" position to turn off the measuring device.

Capacitance Measurement

1. Connecting the Test Leads: Insert the red test lead into the "INPUT" socket and the black test lead into the "COM" socket.
2. Function Selection: Turn the rotary switch to the "<0xE2><0x9A><0xA5>" setting and press the "Select" button. Then select the capacitance function.
3. Connecting to the Capacitor: Connect the test leads to the capacitor to be measured.
4. Reading the Measurement: Read the measurement value from the LCD display. After the measurement, turn the rotary switch to the "OFF" position to turn off the measuring device.

Temperature Measurement

1. Insert the negative (black) plug of the Type-K thermocouple into the "COM" socket and the positive (red) plug into the "INPUT" socket.
2. Function Selection: Turn the rotary switch to the "°C" or "°F" setting.
3. Method: Gently touch the object to be measured with the tip of the Type-K thermocouple.
4. Reading the Measurement: Read the stable measurement value from the LCD display. After the measurement, turn the rotary switch to the "OFF" position to turn off the measuring device.

Frequency Measurement

1. Connecting the Test Leads: Insert the red test lead into the "INPUT" socket and the black test lead into the "COM" socket.
2. Press the "Hz/Duty" button to switch between frequency and duty cycle measurement.
3. Connecting to the Signal Source: Connect the test leads to both ends of the circuit to be measured.
4. Reading the Measurement: Read the measurement value from the LCD display. After the measurement, turn the rotary switch to the "OFF" position to turn off the measuring device.

Maintenance

Battery Replacement

When the "➕" symbol appears on the display, you should replace the batteries immediately.

1. Turn off the measuring device and disconnect the test leads.
2. Loosen the screw and remove the stand to replace the batteries.
3. Remove the old batteries and replace them with new batteries of the same specifications (Size AAA, 1.5 V x 3).
4. Reinstall the stand and secure it with the loosened screw.

Fuse Replacement

Fuses rarely need replacing and usually blow due to operating errors.

1. Turn off the measuring device and disconnect the test leads.
2. Remove the rubber sleeve of the multimeter and loosen the 6 screws. Then remove the back cover to replace the fuses.
3. Remove the blown fuses and replace them with new fuses of the same specifications.
4. Reinstall the back cover and secure it with the screws.

Remark: Always replace a blown fuse with one of the same rating. This measuring device uses two fuses:

• Fuse 1: 500 mA/600 V, Ø5 × 20 mm
• Fuse 2: 10 A/600 V, Ø5 × 20 mm

Troubleshooting

How to Find a Live Wire in an Outlet

1. Switch to voltage measurement.
2. Connect the black test lead to the ground wire or socket. Connect the red test lead to one of the sockets to be tested.
3. Test both sockets. A measurement value should appear on one, while it should remain at or near zero on the other. The live wire is the one where the measurement value appears.

Parasitic Battery Drain in Vehicles

1. Check if the battery voltage and charging are within the normal range. Battery voltage is typically around 12.7 V, and charging is around 14 V.
2. Turn off all electrical accessories inside and outside the vehicle and close the doors.
3. Remove the cover of the negative battery terminal. Set the multimeter to the maximum current range and connect the measuring device in series with the battery.
4. Connect the red test lead to the negative wire and the black test lead to the battery terminal.
5. If necessary, set the measuring device to a lower range.
6. Wait approximately 30 minutes; after all vehicle modules have entered sleep mode, you can read the exact static discharge current. The discharge current is normally 0.02 A (20 mA). This can vary depending on the vehicle. In normal cases, it should not exceed 50 mA.
7. If the discharge exceeds 50 mA, begin by checking the fuses one by one to determine which circuit is causing the overload.
8. If removing a fuse reduces the battery drain to below 50 mA, that specific circuit is responsible for the excessive discharge.

Is the Diode Functioning Correctly?

When the red test lead is connected to the anode of the diode and the black test lead to the cathode, the diode should be in forward bias. The displayed value represents the forward voltage drop.

Normal Forward Voltage Drop for Diodes

For conventional silicon diodes, this is between 0.5 - 0.7 V, and for germanium diodes, it is between 0.15 - 0.3 V.

Method for Determining Polarity

1. Set the multimeter to Resistance.
2. Connect the two test leads to the two electrodes of the diode.
3. Take one reading and then swap the positions of the test leads. Then take the second reading.
4. The higher value is the reverse resistance, and the lower value is the forward resistance. The lower resistance occurs when the black test lead is connected to the positive end of the diode and the red test lead to the negative end.

Specifications

Detailed Specifications

Accuracy is guaranteed for 1 year at storage temperatures of 23 °C ± 5 °C.

DC Voltage (Auto Range)

• Input Impedance: 10 MΩ
• Overload Protection: 600 V DC or 600 V AC RMS (200 mV range: 250 V DC/AC RMS)
• Maximum Input Voltage: 600 V DC

AC Voltage (Auto Range)

• Input Impedance: 10 MΩ
• Frequency Range: 40 Hz ~ 400 Hz
• Overload Protection: 600 V DC or 600 V AC RMS
• Response: Average response time, calibrated to RMS of a sine wave
• Maximum Input Voltage: 600 V AC RMS

Temperature

Note: Different temperature sensors may be configured for different temperature measurement ranges.

DC Current

• Overload Protection: µA and mA ranges: F0.5 A/600 V fuse; 4 A and 10 A ranges: F10 A/600 V fuse
• Maximum Input Current: "INPUT" socket: 200 mA; "A" socket: 10 A
• Voltage Drop: 400 µA, 40 mA, and 4 A ranges: 40 mV; 4000 µA, 400 mA, and 10 A ranges: 400 mV

AC Current

• Overload Protection: µA and mA ranges: F0.5 A/600 V fuse; 4 A and 10 A ranges: F10 A/600 V fuse
• Maximum Input Current: "INPUT" socket: 200 mA; "A" socket: 10 A
• Voltage Drop: 400 µA, 40 mA, and 4 A ranges: 40 mV; 4000 µA, 400 mA, and 10 A ranges: 400 mV
• Frequency Range: 40 Hz ~ 400 Hz
• Response: Average response time, calibrated to RMS of a sine wave

Resistance (Auto Range)

• Open Circuit Voltage: 0.25 V
• Overload Protection: 250 V DC/AC RMS

Diode and Continuity

• Overload Protection: 250 V DC/AC RMS
• For continuity tests: If the resistance is between 50 Ω and 100 Ω, the buzzer may or may not sound. If the resistance is above 100 Ω, the buzzer will not sound.

Capacitance

Frequency

Recycling

You can dispose of the product when it is no longer usable. Please recycle the recyclable parts according to local regulations.

Warranty Period

3-year limited warranty from AstroAI.

Every AstroAI True RMS 4000 Counts Digital Multimeter is free from material or workmanship defects. This warranty does not apply to fuses, disposable batteries, and damage caused by negligence, improper use, contamination, modification, accidents, or abnormal circumstances during use or handling, including overvoltage damage resulting from measurements outside the specified range for the multimeter, as well as normal wear and tear of mechanical components. This warranty is valid only for the original purchaser and is non-transferable.

Should this product be defective, please contact AstroAI Customer Service via support@astroai.com.