Features: VU Meter with stable and reliable performance. Easy to use. Fourth generation driver board design improves performance and optimizes size. Replaces Toshiba 7318 IC with enhanced drive capabilities, addressing previous limitations such as limited pointer swing and low sensitivity. Compact design for easy installation. Well-built and durable construction. Instructions: 1. Use AC or DC 12-15V power supply for the transmission plate. (Independent power transformer recommended, or separate winding power supply; backlight draws 45mA when active.) 2. L, GND, R: Low-level signal input terminals for connecting audio sources such as CD players, computer sound cards, preamplifiers, and other audio devices. Connect L, GND, and R wires individually for left and right channel inputs. 3. R1 and R2 are adjustable resistors on the driver board that control the amplitude of the meter needle movement. 4. The backlight requires a DC 12V power supply and uses a voltage regulator after the driver board. 5. Ensure correct polarity when connecting header interfaces. To extend backlight bulb life: 1. Reduce operating voltage to meet brightness requirements, which can significantly extend bulb lifespan. 2. For AC power (10–12V), use a 10Ω series 50Ω limiting resistor to reduce inrush current on startup. Specifications: Material: Plastic + Metal Color: Black Backlight Voltage: AC/DC 6–12V Measuring Range: 0–500μA ±10% Resistance: 650Ω ±10% Accuracy: ±5% Calibration Point: Full-scale 500μA VU Meter Size: Approx. 35 x 35 x 37mm / 1.38 x 1.38 x 1.46 inches Quantity: 1 Set Note: Please allow 1–3mm variation due to manual measurement. Due to differences in monitor displays, actual item color may vary from images. No retail packaging included. Package Contents: 2 x VU Meter Panels 1 x Driver Board 5 x Cables