In Sequential circuits output is a function of present inputs and pat output. These circuits have a feedback element or memory element which stores the output of the circuit and makes it available at the input. The following is the general diagram of sequential circuits: The binary information stored in the memory element that is […]
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Diode: Doping effect on reverse recovery time
As we have already known that reverse recovery time is the time it takes to invert the minority charge distribution of diode from forward biase to minority charge distribution in reverse biase. Hence when we increase the doping of material, the concentration fo minority charge carriers decrease. Hence as the peaks of charge distribution have […]
DIODE: Reverse Recovery Time
Now let’s analyze that what would happen when we change diode state from forward biase from reverse biase. This state change takes time which is known as reverse recovery time. Consider the following circuit of diode to analyze the switching time of diode. When the diode is in forward biase, the minority charge distribution of […]
Charge distribution of diode
Normal (un-biased) state: Apply the relation given below n * p = ni2 at constant temperature (Mass action law) Now we apply the above relation to p-type: p i.e. the concentration of majority carriers (holes) is larger as doping of p-side is high and we have the value of ni2as constant at fixed temperature. Hence from the […]
Switching time of Diode
The switching time of a diode is defined as the time which a diode takes to change its state from forward biased state to reverse biased state or in other words the forward current through diode doesn’t reduce to reverse saturation current immediately as the reverse voltage is applied. In fact it takes time for […]
Temperature effect on diode
The following graph shows the effect of temperature on the characteristics of diode A-B curve: This curve shows the characteristics of diode for different temperatures in the forward biase. As we can see from the figure given above, that curve moves towards left as we increase the temperature. We know with increase in temperature, conductivity […]
Breakdown of a diode
When the reverse voltage applied across diode becomes greater than the breakdown voltage, then the diode breaks down and very high current starts flowing in the circuit. There are generally two types of breakdowns in a diode: Zener breakdown Avalanche breakdown And based on the above classifications of breakdown of diode, we have the two […]
Diode: Ideal vs Practical
CHARACTERISTICS OF AN IDEAL DIODE When we talk about the ideal diode, the diode is a device which acts as a short circuit when forward biased and acts as open circuit when reverse biased. Hence the behavior of ideal diode can be shown in the following graph: In forward biased, current is zero till the […]
Diode: Reverse Biasing
When the polarity of the external voltage source is opposite to the above case i.e. when positive terminal is connected to n-side and negative terminal to p-side, then diode is said to be reverse biased as shown below: When we reverse bias the diode, the majority carriers have again 3 types of forces acting on […]
Diode: Forward Biasing
When we apply voltage across the diode, as shown below: When the voltage applied across the diode is greater than the barrier voltage, the electrons and the holes present in the n-type and the p-type regions of the diode acquire enough energy to cross the barrier at the junction. Now if we talk in […]