In which region does a transistor work as a switch?
Transistor acts as a switch in the saturation region and cutoff region. The emitter-base junction and the collector-base junction is reverse biased in the cutoff region. Both the junctions are forward biased in the saturation region.
How can an NPN transistor be used as a switch?
NPN Transistor as a Switch Based on the voltage applied at the base terminal of a transistor switching operation is performed. When a sufficient voltage (VIN > 0.7 V) is applied between the base and emitter, collector to emitter voltage is approximately equal to 0. Therefore, the transistor acts as a short circuit.
What is active region in NPN transistor?
Active region is that region in which emitter base junction is forward bias while collector base junction is reverse bias.
What are the two regions of operation for the transistor to act as a switch?
The areas of operation for a transistor switch are known as the Saturation Region and the Cut-off Region.
Do transistors act as a switch?
The transistor operates as a Single Pole Single Throw (SPST) solid state switch. When a zero input signal applied to the base of the transistor, it acts as an open switch. If a positive signal applied at the input terminal then it acts like a closed switch.
How transistor is connected as a switch?
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.
In which regions the transistor act as an open switch & as a closed switch and also give the mode of operation in those regions?
Saturation region This is the region in which transistor tends to behave as a closed switch. The transistor has the effect of its collector and Emitter being shorted. The collector and Emitter currents are maximum in this mode of operation. The figure below shows a transistor working in saturation region.
What is the use of active region of transistor?
The region between cut off and saturation is known as active region. In the active region, collector-base junction remains reverse biased while base-emitter junction remains forward biased. Consequently, the transistor will function normally in this region.
How the transistor acts as a switch?
When a transistor is used as a switch it is?
One of the most common uses for transistors in an electronic circuit is as simple switches. In short, a transistor conducts current across the collector-emitter path only when a voltage is applied to the base. When no base voltage is present, the switch is off. When base voltage is present, the switch is on.
What is NPN transistor switching circuit?
Basic NPN Transistor Switching Circuit. The circuit resembles that of the Common Emitter circuit we looked at in the previous tutorials. The difference this time is that to operate the transistor as a switch the transistor needs to be turned either fully “OFF” (cut-off) or fully “ON” (saturated).
What is the saturation region of a bipolar transistor?
Therefore the transistor is switched “Fully-ON”. Then we can define the “saturation region” or “ON mode” when using a bipolar transistor as a switch as being, both junctions forward biased, VB > 0.7v and IC = Maximum. For a PNP transistor, the Emitter potential must be positive with respect to the Base.
What are the areas of operation for a transistor switch?
The areas of operation for a transistor switch are known as the Saturation Region and the Cut-off Region.
Can a bipolar transistor be used as a switch?
Then we can define the “saturation region” or “ON mode” when using a bipolar transistor as a switch as being, both junctions forward biased, V B > 0.7v and I C = Maximum. For a PNP transistor, the Emitter potential must be positive with respect to the Base.