How does current affect a transistor?
The small current that we turn on at the base makes a big current flow between the emitter and the collector. By turning a small input current into a large output current, the transistor acts like an amplifier. When there is no current to the base, little or no current flows between the collector and the emitter.
What is current gain in a transistor?
The current gain for the common-base configuration is defined as the change in collector current divided by the change in emitter current when the base-to-collector voltage is constant. Typical common-base current gain in a well-designed bipolar transistor is very close to unity.
What happens when the base current of a transistor is increased?
As the base current increases the collector increases proprtionally till the operating point reaches the boundary between the active region and the saturation region. This means while one increases the base current the collector current will remain unchanged because that the transistor enters the saturation region.
Does collector current depend on base 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. Hello Karen A.D.
How is the gain of a transistor calculated?
Transistor gain & Beta, β When undertaking many calculations the transistor current gain is given in terms of the Greek letter Beta; β. This is the forward current gain for the transistor when operated in a common emitter mode. Basic transistor current flows
Why is the gain of a bipolar transistor important?
In any circuit, the current gain of a bipolar transistor will be of paramount importance. Whether the circuit is common emitter, common collector, etc, and whether it uses NPN transistors or PNP transistors.
What is the current gain of a PNP transistor?
For example a BC109B has a current gain h FE between 200 and 450, and a BC109C has a current gain h FE between 420 and 800. Whatever the circuit used, and whether NPN transistors or PNP transistors are used, the current gain of the transistor is a key parameter.
What causes a variation in the Transistor beta?
β variations with collector current: The collector current level can cause a variation in the level of β or or h FE. At low current: This occurs when the bipolar transistor is running at very low current levels as a result of leakage mechanisms being seen and affecting the overall transistor current.