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How are transistors used in solid state switching?
This type of switching application is used for controlling LEDs, motors, lamps, solenoids, etc. A transistor can be used for switching operation for opening or closing of a circuit. This type solid state switching offers significant reliability and lower cost when compared to conventional relays.
How does a Darlington transistor work as a switch?
Darlington Transistors simply contain two individual bipolar NPN or PNP type transistors connected together so that the current gain of the first transistor is multiplied with that of the current gain of the second transistor to produce a device which acts like a single transistor with a very high current gain for a much smaller Base current.
How are transistors used in digital and analog domains?
You can find Transistors in both digital and analog domains as they are extensively used for different application usage like switching circuits, amplifier circuits, power supply circuits, digital logic circuits, voltage regulators, oscillator circuits and so on.
Why are multiple transistors used in a bipolar transistor?
Sometimes the DC current gain of the bipolar transistor is too low to directly switch the load current or voltage, so multiple switching transistors are used. Here, one small input transistor is used to switch “ON” or “OFF” a much larger current handling output transistor.
How is a transistor biased in the saturation region?
Therefore, the transistor is completely in OFF condition. Similarly, in the saturation region, a transistor is biased in such a way that maximum base current is applied that results in maximum collector current and minimum collector-emitter voltage.
How is the output of a bipolar transistor controlled?
It is a current controlled device, where the output current is controlled by the input current. The name bipolar indicates that two types of charge carriers i.e., Electrons and Holes conduct current in the BJT, where holes are positive charge carriers and electrons are negative charge carriers.
What is the base current of a silicon transistor?
For silicon transistor, V BE = 0.7 V Therefore, as the base current is greater than 56.8 micro ampere current, the transistor will be driven to saturation i.e., it is fully ON, when 5V is applied at the input. Thus, the output at the collector becomes approximately zero.