YOJOCK USB Digital Voltmeter Ammeter Wattmeter Instruction Manual

1. Introduction

The YOJOCK USB Digital Voltmeter Ammeter Wattmeter (Model YJ-USB01) is a compact and portable testing device designed for real-time monitoring of USB power delivery. It provides essential data such as voltage, current, power, capacity, energy, equivalent impedance, and temperature, making it an indispensable tool for evaluating the performance of chargers, power banks, cables, and various USB-powered devices. Its wide compatibility with multiple fast charging protocols ensures accurate measurements across a broad range of modern electronics.

Figure 1.1: The YOJOCK USB Tester displaying real-time electrical parameters.

2. Setup and Connection

To begin using your YOJOCK USB Tester, follow these simple steps:

1. Connect to Power Source: Insert the male USB-A connector of the YOJOCK USB Tester into a USB power source, such as a wall charger, power bank, or computer USB port.
2. Connect Device to Test: Plug the charging cable of the device you wish to test (e.g., smartphone, tablet, USB fan) into the female USB-A port on the YOJOCK USB Tester.
3. Begin Measurement: Once connected, the tester's IPS display will automatically illuminate and begin showing real-time measurement data.

Figure 2.1: Connecting the USB tester between a charger and a device for fast charging tests.

Figure 2.2: Illustration of input current and voltage measurement flow.

3. Operating Instructions

3.1 Understanding the Display

The 0.96-inch IPS color display provides a comprehensive overview of the electrical parameters. The screen typically shows:

• Voltage (V): The electrical potential difference.
• Current (A): The flow rate of electric charge.
• Capacity (mAh): The total charge transferred over time.
• Energy (mWh): The total power consumed over time.
• Power (W): The rate at which electrical energy is transferred.
• Equivalent Impedance (Ω): Calculated resistance of the circuit.
• Temperature (°C): Internal temperature of the device.
• Current Time (T): Duration of the current measurement session.
• Group No.: Indicates which data storage group is currently active.

Figure 3.1: The IPS display showing multiple measurement parameters.

Figure 3.2: Explanation of display parameters.

3.2 Data Storage and Clearing

The tester features an intelligent memory storage function, capable of saving up to 9 groups of data. This allows for convenient comparison and analysis of different charging sessions or devices.

• Switching Data Groups: Briefly press the button on the side of the tester to cycle through the 9 data storage groups.
• Clearing Data: To clear the data for the currently displayed group, press and hold the button for approximately 3-5 seconds until the values reset to zero.

Figure 3.3: The intelligent memory storage function allows saving up to 9 data groups.

3.3 Fast Charging Protocol Detection

The tester automatically identifies various fast charging protocols, including QC2.0, QC3.0, iPhone (2.4A/2.1A/1A/0.5A), Android DCP/AFC, FCP(9V/2A), SCP(4.5V/5A), and Super VOOC. This feature helps verify if your charger and device are communicating and utilizing the correct fast charging standard.

Figure 3.4: The tester supports various fast charging protocols like Super VOOC.

4. Maintenance

To ensure the longevity and accuracy of your YOJOCK USB Tester, please observe the following maintenance guidelines:

• Cleaning: Wipe the device with a soft, dry cloth. Do not use abrasive cleaners or solvents.
• Storage: Store the tester in a cool, dry place away from direct sunlight and extreme temperatures.
• Handling: Handle the device with care to avoid physical damage. Avoid dropping or subjecting it to strong impacts.
• Environmental Conditions: Do not expose the device to water or high humidity.

5. Troubleshooting

If you encounter issues with your YOJOCK USB Tester, consider the following common solutions:

• No Display/No Power:
  • Ensure the tester is securely plugged into a functioning USB power source.
  • Verify that the device being tested is drawing power (e.g., charging).
  • Try a different USB port or power adapter.
• Inaccurate Readings:
  • Ensure all connections are firm and free of debris.
  • Test with a known good cable and device to rule out external factors.
  • The tester provides 4-bit precision; minor fluctuations are normal.
• Screen Scratches:
  • While the screen is designed for durability, minor cosmetic imperfections may occur. These typically do not affect functionality.
  • For significant issues, please contact customer support.
• USB 3.0 Speed Limitation:
  • While the tester can measure power for USB 3.0 devices, its internal data lines may operate at USB 2.0 speeds (up to 480 Mbps). This means data transfer rates for connected USB 3.0 devices might be limited when passing through the tester. This is normal operation for this type of device and does not affect power measurement accuracy.

6. Specifications

Figure 6.1: Approximate dimensions of the YOJOCK USB Tester.

7. Warranty and Support

YOJOCK products are manufactured with high standards of quality and reliability. For any questions, technical assistance, or warranty claims, please contact YOJOCK customer service through the retailer where you purchased the product or visit the official YOJOCK website for support information.

Please retain your proof of purchase for warranty purposes.