The name DIAC comes from the words DIode AC switch. These electronic components are also widely used in starter circuits for fluorescent lamps. See full list on electronics-notes. As discrete components they may be contained in small leaded packages, they can be obtained in surface mount packages, in large packages that bolt to a chassis, or a variety of other packages.
DIACs come in a variety of formats.
As they are often used as a DIAC TRIAC combination, they are often integrated into the same die as a TRIAC. DIAC circuits use the fact that a DIAC only conducts current only after a certain breakdown voltage has been exceeded. The actual breakdown voltage will depend upon the specification for the particular component type. By equalising the switching characteristics of these TRIACs, the level of harmonics generated when switching AC signals can be reduced.
Despite this, for large applications, two thyristors are generally used. Interestingly their behaviour is somewhat similar to that of a neon lamp, although they offer a far more precise switch on voltage and thereby provide a far better degree of switching equalisation. (more…)