A blower includes a housing, and an impeller and a motor received in the housing. The motor drives the impeller to rotate. The motor includes a stator and a rotor. The stator includes a stator core and windings wound around the stator core. The stator core includes a yoke and teeth extending from the yoke. A distal end of each of the teeth forms a tooth tip, with a slot opening formed between each two adjacent tooth tips. The rotor includes a permanent magnet forming a plurality of magnetic poles. The stator and the rotor define an air gap therebetween. A circumferential width of the slot opening is equal to or less than two times of a radial width of the air gap.