AstroAI CM4K0R Digital Multimeter
User Manual
Important Safety Information
⚠️ Read this manual carefully before operating the multimeter. Failure to follow safety precautions can result in electric shock, fire, or personal injury.
- Always wear appropriate personal protective equipment (PPE), such as safety glasses.
- Never measure voltage in circuits exceeding the instrument's rated voltage.
- Ensure the test leads and probes are in good condition and properly connected.
- Do not use the multimeter if it appears damaged.
- Avoid using the multimeter in wet or humid environments.
- Disconnect power from the circuit before checking fuses or replacing batteries.
- When measuring current, always connect the multimeter in series with the load.
- Never touch exposed terminals or conductors when the multimeter is connected to a live circuit.
Product Overview
The AstroAI CM4K0R is a versatile 4000-count digital multimeter designed for accurate and reliable electrical measurements in various applications, including electronics, automotive, and household electrical systems. It features auto-ranging for convenient operation and a clear LCD display.
Key Features:
- 4000 Counts LCD Display
- Auto-ranging for Voltage, Current, and Resistance
- DC Voltage Measurement
- AC Voltage Measurement
- DC Current Measurement
- AC Current Measurement
- Resistance Measurement
- Continuity Test (with audible beep ?)
- Diode Test (?)
- Low Battery Indicator (?)
- Overload Protection
Operating Instructions
Selecting Functions: Rotate the central dial to select the desired measurement function. The selected function will be clearly indicated on the display.
Connecting Test Leads:
- Insert the black test lead into the COM (Common) jack.
- Insert the red test lead into the appropriate jack based on the measurement:
- VΩmA jack for Voltage, Resistance, and Current up to 400mA.
- 10A jack for Current measurements up to 10A.
DC Voltage (VDC) Measurement
1. Turn the dial to the VDC position (e.g., V⎓).
AC Voltage (VAC) Measurement
1. Turn the dial to the VAC position (e.g., V~).
DC Current (ADC) Measurement
1. Turn the dial to the ADC position (e.g., A⎓).
AC Current (AAC) Measurement
1. Turn the dial to the AAC position (e.g., A~).
Resistance (Ω) Measurement
1. Turn the dial to the Resistance position (e.g., Ω).
Continuity Test
1. Turn the dial to the Continuity position (often marked with a speaker symbol ? or diode symbol ?).
Diode Test
1. Turn the dial to the Diode Test position (often marked with a diode symbol ?).
Specifications
| Parameter | Specification |
|---|---|
| Display | 4000 Counts LCD |
| DC Voltage | 400mV, 4V, 40V, 400V, 600V ±(0.5% + 3) |
| AC Voltage | 4V, 40V, 400V, 600V ±(1.2% + 5) |
| DC Current | 40mA, 400mA, 10A ±(1.0% + 3) |
| AC Current | 40mA, 400mA, 10A ±(1.5% + 5) |
| Resistance | 400Ω, 4kΩ, 40kΩ, 400kΩ, 4MΩ, 40MΩ ±(1.0% + 4) |
| Continuity | Audible beep for resistance < 30Ω |
| Diode Test | Test current approx. 1mA, Test voltage approx. 3V |
| Power Supply | 1 x 9V Battery (included) |
| Dimensions | Approx. 140 x 70 x 35 mm |
| Weight | Approx. 200g (including battery) |
Maintenance and Care
- Battery Replacement: When the low battery indicator ? appears on the display, replace the 9V battery. Open the rear cover, remove the old battery, and insert a new one, observing correct polarity.
- Cleaning: Clean the multimeter with a soft, damp cloth. Do not use abrasive cleaners or solvents. Ensure the instrument is dry before use.
Troubleshooting
Problem: No display or dim display.
Solution: Check if the battery is low or needs replacement. Ensure the battery is installed correctly.
Problem: Readings are unstable or inaccurate.
Solution: Ensure test leads are securely connected and not damaged. Check for proper range selection. Make sure the circuit is de-energized for resistance measurements.
Problem: Continuity test does not beep.
Solution: Check if the resistance is above the threshold (approx. 30Ω). Ensure the test leads are making good contact.
