嵌入式类电子电路图纸大全 嵌入式类电子电路图全集 一．PWM 马达/灯控制器电路-PWM Motor/Light Controller A pulse width modulator (PWM) is a device that may be used as an efficient light dim mer or DC motor speed controller. The circuit described here is a general purpose devi ce that can control DC devices which draw up to a few amps of current. The circuit m ay be used in 12 Volt and 24 Volt systems with a few minor changes. This device has been used to control the brightness of an automotive tail lamp and as a motor speed c ontrol for small DC fans of the type used in computer power supplies. A PWM circuit w orks by making a square wave with a variable on-to-off ratio, the average on time ma y be varied from 0 to 100 percent. In this manner, a variable amount of power is tran sferred to the load. The m……