Dc motor is dc motor to dc can be converted into mechanical energy (Dc motor)Or can convert mechanical energy into direct current (Dc generator)The rotation of the motor. It is the direct current (dc) can to complete and mechanical energy conversion of the motor. The current of dc motor is rotating armature, is mainly composed of rotor, stator. Including the main pole of the stator, reversing the poles, brush device, frame and end cover; Have armature iron core, the armature winding and the rotor commutator, shaft, bearing. As the name suggests, the stator is in the fixed part of the fixed magnetic field generated; Rotor is rotating parts, produce a change in polarity magnetic field. This is analyze the physical model diagram of the dc motor. Among them, the fixed part have magnet, known as the main pole here; Fixed part and brush. Scroll part has a circular iron core and winding around the annular core. Electric magnetic field around a conductor existence, by ampere force (Wire in a magnetic field by the effect of power)Effect, is due to a direct current, produced in contrast to the main pole polarity, so the conductor move in one direction. Motor rotor stress turned 180 degrees, motor brush automatic conversion direction of current, make the rotor continues to rotate. Magnets, combining played with polarity will repel, different polarity attraction, it is good to understand. This is the basic operation principle of the dc motor. Done to motor current driven element, demand large current. The output current of traditional MCU IO output generally about 10 ma, SCM generally 20 - now25 ma, but there are multiple IO mouth add up the total current constraints, root can't exceed 200 ma, there cannot be more than 400 ma. Take extra voltage 12 v, extra power of 25 w dc motor, demand of operating current is 2 a, 2000 ma. The microcontroller IO port driver talent is not enough. So demand with the drive to control the motor. Here we choose ULN2003, high pressure, high current, internal by seven driver chip made of silicon NPN darlington tube. Here, need to know the chip ULN2003 can expand microcontroller IO port output current, microcontroller to drive motor, must use like ULN2003 drive effect. Dc motor has only two terminals, wiring is simple. In simple terms, one end of the power of the positive and the other end to the cathode, can rotate; If want to make the motor to rotate in the opposite direction just a change of is negative.
