The **KWS-R-1** (commonly part of the KWS series by brands like KEWEISI) is a high-precision digital USB tester used to monitor the charging status of mobile devices, power banks, and USB-powered circuits. --- ## 1. Technical Specifications The device acts as a transparent bridge between a power source (charger) and a load (phone/laptop), measuring the electrical flow through the circuit. | Parameter | Range / Value | | :--- | :--- | | **Voltage Range** | 4V – 30V DC | | **Current Range** | 0A – 5.1A | | **Capacity Accumulation** | 0 – 999,999 mAh | | **Energy Accumulation** | 0 – 999,999 mWh | | **Timing Range** | 0 – 99 Hours | | **Internal Resistance** | 0 – 999.9 Ω | | **Power Rating** | 0 – 150W | --- ## 2. Core Electronic Components The internal architecture of the KWS-R-1 consists of several key electronic subsystems: ### A. The Microcontroller (MCU) The "brain" of the device. It handles the Analog-to-Digital Conversion (ADC) to read voltage and current, performs the math for Power ($P = V \times I$) and Capacity ($C = I \times t$), and drives the display. ### B. Current Shunt Resistor This is a high-precision, low-resistance component (usually a milliohm resistor). The MCU measures the small voltage drop across this resistor to calculate the exact current flowing through the USB port. ### C. Voltage Divider Network Since the MCU cannot directly measure high voltages (up to 30V), a resistor divider scales the input voltage down to a range the MCU can safely process. ### D. Display Module Typically an **IPS Color LCD**. Unlike older 7-segment LED models, the KWS-R-1 uses a high-definition screen to show multiple parameters simultaneously (Voltage, Amperage, Time, Temperature, and mAh). ### E. Non-Volatile Memory (EEPROM) This allows the device to save your data (like mAh and time) even after it is unplugged from the USB port, ensuring you don't lose your charging history. --- ## 3. Key Functions & UI Features * **Real-time Monitoring:** Tracks the health of your battery and the efficiency of your charger. * **Bi-directional measurement:** Some variants can measure current in both directions. * **Protection Alerts:** Some firmware versions include flashing alerts if voltage exceeds 30V or current exceeds 5A. * **Reset Button:** A physical button used to clear the accumulated data (Capacity/Time) or switch between display modes. --- ## 4. Pinout and Connection The device utilizes standard USB 2.0/3.0 physical connectors but is primarily focused on the **VBUS** (Power) and **GND** (Ground) lines for measurement. ```markdown [Input Male USB] ----> [Internal Circuitry] ----> [Output Female USB] | | (Voltage Sense) (Shunt Resistor) ```