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"Transistor" name itself revels it transfers resistance from its input to its output (Transfer of resistance). Input resistance varies when input voltage varies, similarly output resistance varies and this leads to voltage variation at the output. Thus input to output voltage variation is called amplification. this is how transistor can be used as an amplifier.
If input voltage is minimum output voltage becomes maximum i.e. its output resistance becomes maximum in common emitter configuration. Thus if no voltage is applied at the input its collector resistance becomes infinite or as if open circuit. Similarly if input current is increased output current increases and out put can behave as short circuit. This is how output current can be switched off or on using no input current or with minute input current.
Unlike a digital device, the transistor is an analogue device which can be switch on/off to maximum or any gradient in between. Providing a small AC voltage to the base creates an amplified analogue of this signal across the emitter and collector.
What else can I help you with?
Why a transistor is used as a amplifier and switch?
transistor has 2 output 1 and 0 so can be used as a switch
What is use of bipolar junction transistor?
amplifier, switch, oscillator, etc.
How transistor acts as a amplifier?
A transistor does not act as an amplifier. It is used as a component in an amplifier circuit.
What are modes of biasing a transistor?
Transistor works as amplifier,oscillators,switch only when it is biased properly.biasing can be defined as how much amount of voltage that has to be supplied to each junction of the transistor in order to make it work as any one of the above given types.biasing voltage can be decided by seeing the V to I graph of a transistor
What is difference between transistor and amplifier?
A transistor is an electronic component. By itself it has little use. An amplifier is a complete, functional circuit, generally made up of several components. A transistor can be a component part of an amplifier, however an amplifier may be constructed without any transistors (using vacuum tubes instead, for instance).
When a PNP transistor is connected in a circuit it can be used as a power amplifier because?
A PNP transistor has no advantage or disadvantage over an NPN transistor in its ability as an amplifier. Rather, the current-handling capacities of the transistor determine if it's usable as an amplifier.
When transistor acts as an amplifier then does its output voltage increase or decrease?
That depends on both the input signal and the type of amplifier the transistor is used in.
What is an unbiased transistor?
An unbiased transistor is one being used with no bias voltage to offset its operating point. If the input signal is very small it still can operate as an amplifier but the output will be non-linear. One use for an unbiased transistor is when the transistor is used as a switch, turning it on or off.
What are the operating regions of transistors?
operating region of the transistor is the area of the voltage and an electronic configuration in which a transistor can work with its full efficiency. In that operating region transistor can be used easily what above said by harsh is correct...the following may help u further... Based on application the transistor is decided where to lie. for example transistors are made to lie in active region to make it as amplifier. when transistors are used as switch it is made to lie in saturation region(when switch is made as ON) and cut-off region(when switch is made as OFF).....
How transistor works in ac?
work like on off switch!!
What can the input of a transistor be called?
The input of a transistor is typically referred to as the "gate" in a field-effect transistor (FET) or the "base" in a bipolar junction transistor (BJT). In both cases, the input controls the flow of current through the transistor, allowing it to function as a switch or amplifier in electronic circuits. The gate or base receives the input signal that modulates the transistor's operation.
What is the difference between a transistor used as a switch and an amplifier?
A transistor used as a switch is operated in saturated mode, where the ratio of base-emitter current over collector-emitter current is far more than hFe, or beta gain. The transistor is either fully on or fully off in this mode. A transistor used as an amplifier is operated in linear mode, where the ratio of base-emitter current over collector-emitter current is equal to or less than hFe, or beta gain. The transistor is partially on in this mode, and is operating as a current controlled current sink.
