The following are the triggering modes of TRIAC (Triode for alternating current).
- I + mode : The ‘I’ indicates first quadrant operation. The MT2 (main terminal 2) positive with respect to MT1 (main terminal 1). The ‘+’ symbol shows the polarity of gate (G) with respect to MT1 (main terminal 1). In this mode the conduction of current takes place from MT2 to MT1.
- I – mode : The ‘-’ shows the polarity of gate (G) with respect to MT1 (main terminal 1). The conduction of current takes place from MT2 to MT1.
- III + mode : The ‘III’ indicates the third quadrant operation where MT1 (main terminal 1) is positive with respect to MT2 (main terminal 2). The ‘+’ symbol shows the polarity of gate with respect to MT1 (main terminal 1). The conduction of current takes place from MT1 to MT2.
- III – mode : The ‘-’ symbol shows the polarity of gate (G) with respect to MT1 (main terminal 1). The conduction of current takes place from MT1 to MT1.