Germanium with phosphorus

Silicon with aluminium

Germanium with antimony

Germanium with aluminium

Conductor

Insulator

Semi conductor

Resistor

The diode PN junctions

The number of terminals

The device power

Two junction device

To rectify AC to DC

To reduce the ripple

To regulate the voltage

To indicate light

Act as uni directional switch

Act as bi directional switch

Act as control switch

Act as limit switch