The battery internal resistance tester measures internal resistance and voltage simultaneously. It features intelligent control, an LCD display, and a built-in Kalman filter algorithm for efficient and accurate performance. Designed to be lightweight, energy-saving, and cost-effective, it is suitable for use in battery production, maintenance, testing, and research laboratories. It can also measure AC resistance of resistors and low-resistance, high-precision components. The device includes intelligent control, a large display, and a built-in 1000mAh lithium battery for extended operation. It is rechargeable and offers a portable, compact design for easy transport and field use. Equipped with serial port support, it enables communication with a computer for data analysis. The resistance measurement range is 1μΩ to 200Ω, and the voltage range is 0.0001V to ±100V DC. A powerful computer analysis software is included at no additional cost. The serial port is closed by default and must be manually enabled; the default baud rate is 115200. Battery: 1 x 1000mAh lithium battery (included) Measurement speed: 5 times per second Adjustment: Separate calibration for resistance and voltage Basic accuracy: Resistance: 0.5% Voltage: 0.5% Measurement ranges: Resistance: 1μΩ to 200Ω Voltage: 1mV to ±100V DC Test signal frequency: 1kHz AC Test signal current: 20mΩ: 50mA 200mΩ: 5mA 20Ω: 0.5mA Resistance ranges: 6 ranges, automatic and manual Voltage ranges: 3 ranges, automatic and manual Display update rate: 5 times per second Auto power-off: Automatically shuts down after 10 minutes of inactivity Language: Switchable between Chinese and English Item size: 171 x 80 x 29mm (6.73 x 3.15 x 1.14 inches) Packing List (Type 1): 1 x Tester 1 x Probe Packing List (Type 2): 1 x Tester 1 x Clip Packing List (Type 3): 1 x Tester 1 x Probe 1 x Clip Color: As shown Material: Plastic Package type: Standard retail packaging