What does DIAC mean in NASDAQ Symbols?
This page is about the meanings of the acronym/abbreviation/shorthand DIAC in the Business field in general and in the NASDAQ Symbols terminology in particular.
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What does DIAC mean?
- The DIAC, or "diode for alternating current", is a diode that conducts current only after its breakover voltage, VBO, has been reached momentarily. When this occurs, the diode enters the region of negative dynamic resistance, leading to a decrease in the voltage drop across the diode and, usually, a sharp increase in current through the diode. The diode remains "in conduction" until the current through it drops below a value characteristic for the device, called the holding current, IH. Below this value, the diode switches back to its high-resistance state. This behavior is bidirectional, meaning typically the same for both directions of current. Most DIACs have a three-layer structure with breakover voltage around 30 V. Their behavior is somewhat similar to that of a neon lamp, but it is much more precisely controlled and takes place at a lower voltage. DIACs have no gate electrode, unlike some other thyristors that they are commonly used to trigger, such as TRIACs. Some TRIACs, like Quadrac, contain a built-in DIAC in series with the TRIAC's "gate" terminal for this purpose. DIACs are also called symmetrical trigger diodes due to the symmetry of their characteristic curve.