36results about How to "Meet noise requirements" patented technology

Embodiments of the present application provide a control method, device, terminal, and medium for a graphics card fan, which relate to a graphics card heat dissipation technology, and are used to overcome the problem that it is difficult to achieve both good heat dissipation effect and noise reduction in related technologies. The control method includes: obtaining the current temperature of the graphics card, determining the current temperature deviation of the graphics card; the current temperature deviation is the difference between the current temperature and the set temperature; determining the pulse width modulation PWM duty cycle according to the current temperature deviation Duty ratio: when the PWM duty ratio exceeds the maximum duty ratio corresponding to the noise requirement, the speed of the graphics card fan is controlled according to the maximum duty ratio.

The invention discloses a composite cold pressing, synthesizing and cementing carrier roller which comprises combination sealing devices, a pipe base, check rings, bearings, spacer rings and a shaft. The shaft penetrates the pipe base, the spacer rings and the bearings are arranged at the two ends of the shaft, and the bearings are fixed to the two ends of the shaft through the check rings. The combination sealing devices penetrate the shaft to be in interference connection with the pipe base to be arranged at the two ends of the shaft. The pipe base is formed by connecting a pipe and bearing pedestals into a whole in a cold pressing, synthesizing and cementing manner, the pipe is made of a straight-line electric welding steel pipe special for an ultrahigh-precision carrier roller through inner and outer pipe rust prevention treatment. The bearing pedestals are made of polyformaldehyde through one-time injection moulding. The production procedure of the bearing pedestals is simplified, the precision of the finished bearing pedestals is improved, the weight is low, and strength is high; and the assembling mode of the bearing pedestals and the steel pipe is simplified, noise is lowered, and the carrier roller is applied to the field of bulk material conveying equipment.

The invention discloses a fine dimming device for a light emitting diode (LED) module. According to the device, a first pulse width modulation (PWM) signal output interface of the central processing unit (CPU) is connected with a signal input end of a first field-effect transistor; a signal output end of the first field-effect transistor is connected with a control end of the LED module through a current-limiting module; a second PWM signal output interface of the CPU is connected with a signal input end of a second field-effect transistor; and a signal output end of the second field-effect transistor is connected with the control end of the LED module. A dimming method comprises the following steps of: 1, judging whether luminosity corresponding to the light illumination which is required to be output by the LED module is greater than 5 percent of the maximum luminosity of the LED module; 2, if the luminosity is not greater than 5 percent of the maximum luminosity of the LED module, controlling the LED module to illuminate through a first PWM control signal by the CPU; and 3, if the luminosity is greater than 5 percent of the maximum luminosity of the LED module, controlling the LED module to illuminate after the first PWM control signal and the second PWM control signal which are sent by the CPU are superposed. According to the method, the ratio of the minimum illumination output to the maximum illumination output exceeds 1:10,000, so the dimming fineness of the LED module is guaranteed.