Rithick technology

Diode as a Circuit Element  Consider a simple diode circuit shown in the Fig. 1 in which a d.c. voltage of is applied to load resistance through a diode. The output is voltage across the resistance. Fig. 1  Simple diode circuit        Apply  Kirchhoff's  voltage law to the circuit,             -V f  - I f  R L  + V in  = 0        The aim is to obtain V f  as well as the current I. Thus there are two unknowns and on equation.        The second equation is provided by the diode current equation as,         But solving these two equations is not easy due to an exponential term. The solution gives transcendental which can not be solved directly. Hence the graphical method is used to solve these equations. 1.1 Static Characteristics and the Load Line...

PN junction breakdown characteristics In this article, we are going to learn a little deep about break down characteristics of PN Junction Diode and how “reverse break down” characteristics is put into practical applications. Before getting into the details, lets have a walk through our previous articles. 1.  Understanding the PN Junction  –  is a great article to begin your learning curve about pn junction. In this article, we have clearly explained what is a pn junction and how is it formed. 2.  PN Junction Characteristics – is another great article you must read to understand behavior of a PN junction under different conditions; say forward bias and reverse bias . This article will also help you understand why a PN junction is used in rectification applications. Now lets comes to the essence of this article. “Break down” of a diode occurs during its reverse biased condition.  We all know, under reverse bias the positive terminal of battery is conne...

Junction diode switching characteristics The effect described in the previous tutorial is achieved without any external voltage being applied to the actual PN junction resulting in the junction being in a state of equilibrium. However, if we were to make electrical connections at the ends of both the N-type and the P-type materials and then connect them to a battery source, an additional energy source now exists to overcome the potential barrier. The effect of adding this additional energy source results in the free electrons being able to cross the depletion region from one side to the other. The behaviour of the PN junction with regards to the potential barrier’s width produces an asymmetrical conducting two terminal device, better known as the  PN Junction Diode . A  PN Junction Diode  is one of the simplest semiconductor devices around, and which has the characteristic of passing current in only one direction only. However, unlike a resistor, a diode does...

Explain the effect of temperature on PN junction diode. PN junction diode parameters like reverse saturation current, bias current, reverse breakdown voltage and barrier voltage are dependent on temperature. Mathematically diode current is given by I = I S ∗ ( e x p ( ( V / ( n ∗ k ∗ T / q ) ) ) – 1 ) I = I S ∗ ( e x p ( ( V / ( n ∗ k ∗ T / q ) ) ) – 1 ) Hence from equation we conclude that the current should decrease with increase in temperature but exactly opposite occurs there are two reasons: Rise in temperature generates more electron-hole pair thus conductivity increases and thus increase in current Increase in reverse saturation current with temperature offsets the effect of rise in temperature Reverse saturation current  ( I S ) ( I S )  of diode increases with increase in the temperature the rise is 7%/ºC for both germanium and silicon and approximately doubles for every  10 º C 10 º C  rise in temperature. Thus if we kept the voltage constant,...