How does the Shockley equation modify during forward and reverse biasing of a pn junction diode?
Under reverse bias (when the n side is put at a more positive voltage than the p side) the exponential term in the diode equation is near zero and the current is near a constant (negative) reverse current value of −IS. The reverse breakdown region is not modeled by the Shockley diode equation.
How characteristic will vary for a real diode?
Real Diode Characteristics. Ideally, diodes will block any and all current flowing the reverse direction, or just act like a short-circuit if current flow is forward. Diodes do consume some amount of power when conducting forward current, and they won’t block out all reverse current.
When is the Shockley ideal diode equation equal to 1?
The equation is called the Shockley ideal diode equation when n, the ideality factor, is set equal to 1.
How does Shockley calculate the total voltage drop?
To derive his equation for the voltage, Shockley argues that the total voltage drop can be divided into three parts: the drop of the quasi-Fermi level of holes from the level of the applied voltage at the p terminal to its value at the point where doping is neutral (which we may call the junction)
Why is the ideality factor added to the diode equation?
The ideality factor n typically varies from 1 to 2 (though can in some cases be higher), depending on the fabrication process and semiconductor material and is set equal to 1 for the case of an “ideal” diode (thus the n is sometimes omitted). The ideality factor was added to account for imperfect junctions as observed in real transistors.
What is the relationship between voltage and current of a diode?
Diode Law Graph, shows relationship of voltage and current of an ideal diode The Shockley diode equation or the diode law, named after transistor co-inventor William Shockley of Bell Telephone Laboratories, gives the I–V (current-voltage) characteristic of an idealized diode in either forward or reverse bias (applied voltage):