Diode is formed by envelope tubal core and two electrode

 Diode is formed by tubal core, envelope and two electrode. Be in charge of core is knot of a PN, the two end that written guarantee in PN each are derivative a down-lead, serve as with plastic, glass or metallic stuff enclose crust, made crystal diode, following plan institute are shown. The derivative electrode of P area calls positive electrode or positive pole, the derivative electrode of N area calls negative pole or cathode.