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By turning a small input current into a large output current, the transistor acts like an amplifier. But it also acts like a switch at the same time. When there is no current to the base, little or no current flows between the collector and the emitter. Turn on the base current and a big current flows.
How does current flow through a transistor?
We know that in transistors and diodes, electric current is carried by both free electrons and holes. Free electrons and holes travel in opposite directions. For example, if free electrons flow from left to right then the holes will flow from right to left.
What is transistor and its working principle?
The basic idea behind a transistor is that it lets you control the flow of current through one channel by varying the intensity of a much smaller current that’s flowing through a second channel. A transistor is a semiconductor device with three terminals, capable of amplification and rectification.
How a transistor works as a switch?
With a zero signal applied to the Base of the transistor it turns “OFF” acting like an open switch and zero collector current flows. With a positive signal applied to the Base of the transistor it turns “ON” acting like a closed switch and maximum circuit current flows through the device.
How does a transistor amplify?
A transistor acts as an amplifier by raising the strength of a weak signal. The DC bias voltage applied to the emitter base junction, makes it remain in forward biased condition. Thus a small input voltage results in a large output voltage, which shows that the transistor works as an amplifier.
How does a transistor work simple?
A transistor works when the electrons and the holes start moving across the two junctions between the n-type and p-type silicon. The small current that we turn on at the base makes a big current flow between the emitter and the collector.
What are uses of transistor?
Transistors have extensive uses in our day to day life. They are used in nearly every kind of circuit in order to perform a function. A few applications of transistors are: switches, amplifiers, oscillators, modulators, detectors, BJT, FET, HBT, avalanche transistor, etc.
How is transistor biasing done?
Biasing is the process of providing DC voltage which helps in the functioning of the circuit. A transistor is based in order to make the emitter base junction forward biased and collector base junction reverse biased, so that it maintains in active region, to work as an amplifier.
How is a transistor connected in a circuit?
To connect the transistor as a switch in a circuit, we connect the output of the device that will switch on the transistor to the base of the transistor. The emitter will connect to ground of the circuit. And the collector will connect to the load that the transistor will turn on and the supply voltage of the circuit.
Does transistor work on AC or DC?
As we said before, transistors are DC components. This means that the output will also be a DC voltage. But if we amplify an AC voltage, then we probably want to get an AC voltage at the output as well.
Is transistor a diode?
The main difference between diode and transistor is that transistor is a three terminal device which passes current from high resistance region to low resistance region while the diode is a two-terminal device which current in only one direction from the anode to the cathode.
How do diodes work?
A diode is an electronic component that directs the flow of electricity in one direction. They are called “active components,” the same as transistors and ICs. When a voltage is applied, the free electrons in the metal crystal move around and carry an electric charge, which is how electricity flows.
Does transistor increase current or voltage?
Transistor is a current controlled current device. So it amplifies current and not voltage. But it is also impossible to introduce current in a transistor without any voltage. Hence, we bias the transistor properly such that we can provide input current for amplification.
Does transistor amplify DC voltage?
Yes, transistors amplify DC. The input DC is amplified to the base, and this amplified current is extracted by at the collector.
How do BJT transistors work?
A BJT is a type of transistor that uses both electrons and holes as charge carriers. A signal of small amplitude if applied to the base is available in the amplified form at the collector of the transistor. This is the amplification provided by the BJT.
How does a PNP transistor work?
The PNP transistor is a type of transistor in which one n-type material is doped with two p-type materials. When a small current flow through the base of the PNP transistor, it turns on. The current in a PNP transistor flows from the emitter to the collector.
How do NPN transistors work?
How does BJT Work? For an NPN transistor, it consists of a layer of P-doped semiconductor between two layers of N-doped material, where electrons are passed from the emitter to the collector instead. The emitter then “emits” electrons into the base, with the base controlling the no. of electrons the emitter emits.
How many terminals does a transistor have?
Transistor – a three-terminal device for which the voltage or current at one terminal controls the electrical behavior of the other terminals.
Why was the transistor so important?
The transistor went on to replace bulky vacuum tubes and mechanical relays. The invention revolutionized the world of electronics and became the basic building block upon which all modern computer technology rests.
Who invented transistor?
The three physicists who invented the transistor; William Shockley, John Bardeen, and Walter Brattain were awarded with the Nobel Prize.
