4-Channel 12V 4-Pin PWM Fan Controller with Manual Knob for PC Case and Server

Product overview and key benefits. - Precise manual PWM control for 4 DC 12V fans gives flexible speed adjustment in multi-fan setups, enabling quieter operation and targeted cooling. - Stable power delivery with up to 3 A total output supports multiple fans in cases, servers, or small racks while maintaining consistent rotation and reliability. - Simple, intuitive operation with a rotary knob and built-in power switch makes setup and daily use fast and user friendly. - High-frequency 5 V 25 kHz PWM output enables smooth fan response and fine speed resolution across the full 0 to 100 percent duty range. Main features and what makes this product useful. - Four-wire PWM speed control technology provides independent PWM signaling compatible with standard 4-pin PWM fans and allows precise manual adjustment via a knob. - Integrated on/off switch allows quick start and stop of connected fans without disconnecting power. - Low idle board consumption under 20 mA when no fans are connected conserves system power. - Adjustable start-speed trimmer on the PCB sets the minimum PWM level to ensure reliable fan startup at low setpoints. - Direction adjustment option for fans with reversed PWM wiring is available via a PF pad, which can be shorted while power is off to invert the PWM direction. Technical specifications. - Operating voltage: nominal DC 12V, operable from 8 V to 15 V, provided all connected fans share the same supply voltage. - Maximum combined fan current: 3 A total for all connected fans; allow margin below the maximum for safe operation. - Board quiescent current: less than 20 mA when no fans are attached. - PWM signal: 5 V amplitude at 25 kHz frequency. - PWM output duty range: 0 percent to 100 percent. - Initial PWM adjustment range: 0 percent to 60 percent for start-up tuning. - Output connector: 2510-4P offset style, compatible with standard CPU and case 4-pin fan connectors, pin spacing 2.54 mm. Compatibility and limitations. - Designed exclusively for 12 V four-wire PWM fans that support PWM speed control, such as many CPU and case fans. - Two-wire and three-wire fans are not controllable with this device and must not be expected to respond to PWM signals. - Ensure all fans connected to the controller use the same voltage within the specified range. Basic operation and safety notes. - Observe correct polarity and the rated supply voltage before connecting the device and fans. - Connect the power supply and fans, then use the rotary knob to set fan speed; turning the knob counterclockwise sets minimum output and turning clockwise increases output. - Use the small adjustable resistor on the PCB to set the starting PWM level for low-speed startup. - If a fan spins opposite to the intended direction due to reversed PWM wiring, power off the unit, short the PF pad with solder to invert the PWM direction, and then power on. Always disconnect power before making PCB modifications to avoid damage. - Do not attempt to control non-PWM two- or three-wire fans, and do not exceed the 3 A combined current rating. Practical applications and use scenarios. - Desktop PC and workstation cooling: fine-tune case and CPU fan speeds for a balance between noise and thermal performance. - Small server or home lab racks: synchronize multiple 12 V PWM fans while limiting noise during light workloads. - Network attached storage or media enclosures: lower fan speeds to reduce audible noise during low-load periods while retaining the ability to increase airflow when needed. This device provides a compact and reliable solution for manual PWM speed control of 12 V four-wire fans in multi-fan systems while offering simple operation, stable power delivery, and provisions for start-speed adjustment and PWM direction correction.