Static v- i characteristics - power semiconductor devices, Electrical Engineering

V- I Characteristics

The operation of the  diac can be explained by imagining it as two diodes connected  in series. When  applied voltage in either polarity is small ( less than break over voltage) a very  small amount  of current called the  leakage current flows  through the diac. Leakage  current caused due to the drift of  electrons and holes in the depletion region is not  sufficient to cause conduction in the device. The device remains in non conducting mode. How ever when T1 is positive with  respect to T1 the layers P-N-P-N starts conducting only  when applied  voltage of T1 exceeds break over voltage  V boi . once the conduction starts the current through the diac becomes very  large  and has to be limited by the external resistance in the circuit.

When T2 positive  with respect to Tp  the layers P-N-p-N  conduct. This happens when the applied voltage of T2 exceeds break over voltage  V Bo2. In both  the cases the current during  blocking regions are small  leakage current . the  behaviour  in both  the directions are  is similar  because doping level   is same in all the  layers in tow directions. The break  over  voltage  for commonly  used  disc is about 30v.

When T1 is positive  and voltage  is less than Vbo1 only a small  leakage current  flows  through  the device. When voltage  exceeds  Vboi it starts  conducting and  current  becomes  large. As the current increase the voltage  drop  across diac decrease.  Thus  it exhibit negative resistance characteristics. The  characteristics of diac  in reverse direction when  T2  is positive  lies in  the third quadrant and is  exactly similar to that in the first  quadrant. The break over voltage  VBOi and V Bo2 are exactly equal in magnitude. In both  the cases the device exhibits negative  resistance behaviours  during  conduction  region. Diac is mainly used for triggering triacs.

Posted Date: 4/2/2013 7:14:19 AM | Location : United States







Related Discussions:- Static v- i characteristics - power semiconductor devices, Assignment Help, Ask Question on Static v- i characteristics - power semiconductor devices, Get Answer, Expert's Help, Static v- i characteristics - power semiconductor devices Discussions

Write discussion on Static v- i characteristics - power semiconductor devices
Your posts are moderated
Related Questions
Q. Define amplification factor? Amplification factor  μ It is the ratio of the drain -source voltage (ΔVDS) to the change in the gate to source voltage (ΔV GS ) at constan

Describe the construction and working of atleast two types of storage CRO

Switching Characteristics Switching  characteristics  of BJT  are shown  in figure. Due  to the presence of internal  capacitances BJT  cannot be  turned  instantly. Initially

Transistor as a switch: Transistors are generally employed as electronic switches, for both of the high power applications including switched-mode power supplies and low power

The assignment is to plan, design and write a PLC program on the FX Training Software using a PART SUPPLY CONTROL SYSTEM based on the requirement specification outlined be

voice signal is measured at 3.21692v and resides in an interval from 3.20v to 3.30. How big is an interval? MAx possible voltage?

Q. Use (a) mesh analysis and (b) nodal analysis to determine the voltage ¯V at the terminals A-B of Figure.

Question: General EMC Knowledge (a) Give 2 reasons for the augmentation of electromagnetic radiation in urban regions. (b) Pointe aux Diable bears its name due to the a

Q. For the configurations of the coupled coils shown in Figure, obtain the voltage equations for v 1 and v 2 .

Quantization Error Sampling followed by quantization is equivalent to quantization followed by sampling. Figure illustrates a message signal f (t) and its quantized version den