TRANSFORMER, MAGNETIC CORE AND BOBBIN THEREOF

A transformer includes a magnetic core assembly, a bobbin, and a winding coil assembly. The magnetic core assembly includes a first magnetic core and a second magnetic core. Each of the first magnetic core and the second magnetic core includes a magnetic plate, a center leg, a first lateral leg, and a second lateral leg. The first lateral leg and the second lateral leg are disposed on two opposite edges of the magnetic plate. The magnetic plate has a thinned region. The thinned region is defined by the first lateral leg, the second lateral leg and the center leg collaboratively. The bobbin has an engaging structure corresponding to the thinned region. When the bobbin is arranged between the first magnetic core and the second magnetic core, the engaging structure of the bobbin is engaged with the thinned region. The winding coil assembly is wound on the bobbin.