Table of Contents
- 1 Why is the base region of a BJT narrow?
- 2 Why is the width of the base region of a transistor kept very small than other regions?
- 3 Why is base current less?
- 4 Why is a narrow base good for transistor β?
- 5 What is base width modulation Early effect in transistor Mcq?
- 6 What is the most important characteristic of BJT?
- 7 What is a BJT transistor?
Why is the base region of a BJT narrow?
Explanation: The base is thin so the collector junction depletion region basically fills the base space. This means that the majority carriers from the forward biased emitter junction, being minority carriers for the collector junction, are, therefore, swept across the reverse-biased collector-base junction.
Why the base region has the smallest width?
The width of base is kept small because as we know it is lightly doped & contains less charge carries & requires less current (2\%-5\%) to flow in base region & for collection of maximum charge carries coming from emitter in collector as base offers less resistance hence it’s width is small .
Why is the width of the base region of a transistor kept very small than other regions?
Why the width of the base region of a transistor is kept very small compared to other regions? Base region of a transistor is kept very small and very lightly doped so as to pass most of the injected charge carriers to the collector.
What is base narrowing?
Base narrowing has two consequences that affect the current: – There is a lesser chance for recombination within the “smaller” base region. – The charge gradient is increased across the base, and consequently, the current of minority carriers injected across the emitter junction increases.
Why is base current less?
Answer: Base is much narrower and thinner than collectors,hence the majority of charge carriers are received by collector. Hence,collector current is greater than base current.
Why the base is thin in transistor?
The base region in a transistor is made very thin so that there is a better conduction of majority carriers from emitter to collector through base. The base region in a transistor is doped lightly so that the number density of majority carriers (electrons in p-n and holes in n-p-n transistor) is low. …
Why is a narrow base good for transistor β?
Consider if the base thickness were large. In this case the distance to travel is much greater and the probability of recombination increases, hence the Beta of the transistor (Ic/Ib) decreases. The base region of a bipolar transistor needs to be narrow to maximize current gain and minimize base transit time.
What is an Early effect and how it affects the collector current?
The emitter–base junction is unchanged because the emitter–base voltage is the same. Both these factors increase the collector or “output” current of the transistor with an increase in the collector voltage, but only the second is called Early effect.
What is base width modulation Early effect in transistor Mcq?
The phenomenon known as ‘Early effect’ in a bipolar transistor refers to a reduction of the effective base-width caused by. Electron-hole recombination at the base. The reverse-biasing of the base-collector junction. The forward-biasing of the emitter-base junction.
Why collector current is less than emitter current?
The base contains more holes than electrons. As the direction of current is opposite to the flow of electrons we can understand that current from the emitter is conducted to the base and the collector. Hence, the collector current will always be slightly less than the emitter current.
What is the most important characteristic of BJT?
The most important characteristic of the BJT is the plot of the collector current, the collector-emitter voltage, CE, for various values of the base current, I
What is common emitter configuration in BJT?
Common Emitter Configuration – shows both Current and Voltage Gain. Common Collector Configuration – shows Current Gain but no Voltage Gain. In a common base mode which is also called grounded base, the base terminal of the BJT is used as the common terminal for both input and output of the configuration.
What is a BJT transistor?
Transistors: Bipolar Junction Transistors (BJT) General configuration and definitions The transistor is the main building block “element” of electronics. It is a semiconductor device and it comes in two general types: the Bipolar Junction Transistor (BJT) and the Field Effect Transistor (FET).
What is the extreme case of base-width modulation?
An extreme case of base-width modulation is punchthrough. As the collector-emitter voltage is increased, the quasi-neutral width of the base decreases, so that it eventually becomes zero. The collector current becomes very large and no longer depends on the voltage applied to the base.