12V 24V 48V 110V 5V 110V Max 10A DC Motor Speed Control PWM Mach3 Speed Control | eBay
5.Except the board inside a PWM speed control , can also support an external PWM signal input speed control , external PWM input requirements : level 3.5 - 12V VPP , the frequency of 1K - 10KHZ , in particular apply in MCH3 spindle speed control ....