definitions

-
Explain the following:

(I) PN junction diode in forward bias:-

When a diode is connected in a forward bias condition a negative voltage is applied to the n type material and a positive voltage is applied to the P type material. If the external voltage becomes greater than the value of potential barrier which is 0.7 volt for Silicon and 0.3 for Germanium then current will start to flow. 

(II) Zener effect:-
Zener Effect /diode is a type of electrical breakdown. it occurs in the reverse bias PN junction diode when the electric field enables tunneling of the electron from the valence to the conduction band of a semiconductor, leading to numerous free minority carrier which suddenly increased the reverse current. 

(iii) Avalanche effect : -
It is a sudden rapid increase in the current when a sufficient amount of electrical force is applied to the semiconductor material. 

(iv) Reverse saturation current :-
It is a kind of leakage current or invented current flows when Semiconductor devices are reverse bias. 


Comments

Post a Comment

Popular posts from this blog

question 1

-
Image
Calculate the maximum DC voltage available from a half wave rectifier Shown . Also find the reading of the milli ammeter.  Solution:- Turn ratio of transformer = 20:1 Number of turns in primary binding = 20 Number of turns in secondary binding = 1 Mains voltage supply(1/p) Vp = 220 v From the Transformer ratio formula Np/Ns = Vp/Vs 20/1 = 220/ Vs Vs = 220/20 = 11V Vrms = Vm/√2  => Vm = Vrms √2 => Vm = 11 √2 Vm = 15.5563 v Vdc =  2Vm /π Vdc = 2×15.5563/π = 9.90V I = V/R => 9.90/1×1000 I = 9.90mA
Read more

Trapezoidal rule 4

-
Image
Evaluate By (I) Trapezoidal rule ,  (ii) Simpson's one - third rule, correct to four decimals taking  h = 0.1 Solution :- h=0.1  Y = f(x)  X                   Y 0                    0 0.1                 0.00999 0.2                 0.03998 0.3                 0.08987 0.4                 0.15932 0.5                 0.24740 0.6                 0.35227 0.7                 0.47063 0.8                 0.59719 0.9                 0.72428 1.0                 0.84147 (I) Using Trapezoidal rule Integration of y dx = h/2 [( y0 + yn) + 2(y 1 + y 2 +.... ...... + y (n-1) ] => 0.1/2[(0 + 0.84147) + 2(0.00999 + 0.03998 + 0.08987 + 0.15932 + 0.24740+ 0.35227 + 0.47063 + 0.59719 + 0.72428) ] => 0.05 [ 0.84147 + 2× 2.69093 ] => 0.05 [ 0.84147 + 5.38186 ] => 0.05 × 6.22333 => 0.3111665 (ii)  Using Simpson's 1/3rd rule.  Integration of y dx = h/3  [( y 0 + y n ) + 4 (y 1 + y 3 +.... ...... + y(n-1) + 2(y 2+ y4 + .......... + y (n - 2)  ] => 0.1/3 [ ( 0 + 0.8414
Read more

kinematics 12th

-
  A body is thrown vertically upwards with an initial velocity u reaches the maximum height in 6s. The ratio of the distance traveled by the body in first second to seventh second is   Initial velocity u = g×t = 9.8 ×6 = 58.8 m/s   distance S 1 travelled in first second is calculated using " S = u ×t - (1/2)×g×t 2  ", using u = 58.8 m/s, and t = 1 s;   S 1  = 58.8 ×1 -(1/2) ×9.8 ×1 ×= 53.9 m   Since the paticle reaches maximum height in 6 s, at 7th second travel, its initial velocity is zero.   hence distance S 7  travelled in 7th second = (1/2) ×9.8 ×1 ×1 = 4.9 m   hence the ratio S 1  / S 7  = 53.9 / 4.9 = 11  
Read more