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How do you calculate reverse bias saturation current?
Hint: We know that the current that flows in reverse bias PN junction diode is called reverse saturation current. From the diode current equation I=Is(eVηVT−1) the current should decrease as the temperature is increased but the opposite happens.
What is reverse saturation current in BJT?
The saturation current (or scale current), more accurately the reverse saturation current, is that part of the reverse current in a semiconductor diode caused by diffusion of minority carriers from the neutral regions to the depletion region. This current is almost independent of the reverse voltage. (
How is the saturation of a BJT determined?
Saturation (for a BJT) is defined in several ways, but generally it relates to the collector-emitter voltage V CE. Here is an LTSpice simulation of a 2N4401 transistor driving a 160 ohm load with a 5V supply, which corresponds to about 30 mA collector current with the transistor turned ON.
What do you mean by reverse active in BJT?
In the OFF state, the transistor acts as an open switch, so no current flows through. In the ON state, it acts as a short circuit, so current can flow through uncontrolled. In the ACTIVE region, the transistor does something special. It amplifies.
How to calculate the saturation of a transistor?
Divide the maximum collector current (I C) by the minimum current gain (h FE) at that collector current. For example, say I C (max) = 30 mA and h FE (min) = 83 at I C = 30 mA. The result is that I B (nominal) is about 360 µA. Multiply I B (nominal) by a “saturation factor” – a number between 2 and 10 – to ensure that the transistor saturates.
When do you use a bipolar junction transistor?
When a bipolar junction transistor (BJT) is used to switch a load (e.g. a relay, an LED, a buzzer, a small motor, etc) ON and OFF, it is most often operated as a “saturated switch”. This article explains saturation in BJTs – why it is used, and how to calculate the base resistor to ensure saturation.