Table of Contents
What is the reason for smaller base current in BJT?
In a BJT, the base current is small because the base region is small and the reverse biased collector junction voltage draws most of what are now minority carriers into the collector before they can exit the base.
How does base current control collector current?
Hello, The base current controls the collector current when the transistor is in the active region. A transistor is made up of two PN junctions, an emitter junction and a collector junction. The active region is when the emitter junction is forward biased and the collector junction is reverse biased.
How current is controlled in BJT?
BJT is current controlled due to the relationship between input (base current) and output (collector current). Ic = BETA*Ib. Where BETA is relatively constant over several decades of current. The MOSFET controls the channel charge based on the gate bias voltage (relative to source & bulk).
What is base width modulation in BJT?
Early effect or base width modulation: The early effect is the variation in the width of the base in a bipolar transistor due to a variation in the applied base-to-collector voltage. For example a greater reverse bias across the collector- base junction increases the collector-base depletion width.
How do you increase current in a circuit using transistor?
For instance:
- I=VR=50V250Ω=200mA. or also.
- I=VR=5V25Ω=200mA. A transistor can be used to increase current. You’ll have a low current path, from base to emitter in an NPN, and a higher current path from collector to emitter.
- R=VI=3V0.02A=150Ω; If you use a 150 Ω resistor in series with the LED you’ll get 20 mA.
How does base current affect collector current in BJT?
The base current in the BJT is due to the recombination of holes and electrons. To neutralize the p region an electron leaves the p region. If we take it the other way round, the larger the base current the greater is the recombination, so the collector current should reduce, but Beta Ic/Ib.
What is the base current of a transistor?
, student of electronics since 1999. The base current controls the collector current when the transistor is in the active region. A transistor is made up of two PN junctions, an emitter junction and a collector junction. Transistors are controlled by a voltage applied between the emitter and base.
What are the properties of a bipolar junction transistor?
One of the most important properties of the Bipolar Junction Transistor is that a small base current can control a much larger collector current. Consider the following example. A bipolar NPN transistor has a DC current gain, ( Beta) value of 200. Calculate the base current Ib required to switch a resistive load of 4mA.
Which current controls the collector current in a transistor?
The base current controls the collector current when the transistor is in the active region. A transistor is made up of two PN junctions, an emitter junction and a collector junction.