This document provides information about DIAC (Diode Alternating Current). It defines DIAC as a semiconductor device that allows current to flow in one direction. The document discusses the structure of DIACs, which can have npn or npnpn layers. It explains that DIACs operate in both forward and reverse polarities, and conduct only after exceeding a breakdown voltage, entering a region of negative resistance. The document includes the symbol for DIACs and provides examples of its applications, such as in lamp dimmer circuits, heat control circuits, and motor speed control.

2. introduction
Name
Hamza Sajid 
enrollment no
16-Arid-7
class
BS-IT (3rd sem)
submitted to:
Sir Azmatullah

3. DIAC::--
It means that Diode alternating
current

4. Definition:-  
 A semiconductor device with two terminals,
typically allowing the flow of current in one
direction only.
 It have two electrodes (an anode and a
cathode).

5. Structure of DIAC:-  
There are fallowing types of DIAC
according to layers:-
npn
npnpn
Symbol of DIAC:-

6. Working of DIAC:-  
 DIAC operates in both forward and positive polarities. And
DIAC is essentially a diode that conducts after a ‘break-
over’ voltage is exceeded. Until the device exceeds the
break-over voltage, the resistance of it is very high. When
it exceeds the break-over voltage, it enters the region of
negative dynamic resistance. As a result, a decrease in
the voltage drop across the diode takes place with
increasing voltage and a sharp increase in the level of
current conducted by the device takes place.

7. Circuit diagram:-  

8. Graphical representation of DIAC:-  

9. Application of DIAC:-  
It can be used in the lamp dimmer
circuit.
It is used in the heat control circuit.
It is used in the speed control of a
universal motor.

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