Table of Contents
- 1 How a BJT works as a variable resistor?
- 2 Where is a variable resistor used?
- 3 Can a transistor be used as a variable resistor?
- 4 Between which regions does BJT act like switch?
- 5 Why does a variable resistor work?
- 6 What is a variable resistor called?
- 7 How many regions of BJT are there?
- 8 Is a transistor a resistor?
How a BJT works as a variable resistor?
BJT’s are current-driven devices i.e. It is a current-controlled device. The current through the two terminals is controlled by a current at the third terminal (base). It has a low input impedance. Emitter junction is forward biased and collector junction is reverse biased BJT works as a variable resistance.
Where is a variable resistor used?
A variable resistor is used in some dimmer switches and volume controls. The resistance of a thermistor depends on its temperature.
How do you know if BJT is in active region?
For the BJT to operate in the active region, the condition is that the base-emitter junction should be forward-biased while the base-collector junction is reverse-biased.
Can a transistor be used as a variable resistor?
Yes, a transistor is like a variable resistor, in that the resistance between collector-emitter or drain-source is variable. It’s like a valve, and either allows current to flow or blocks it from flowing.
Between which regions does BJT act like switch?
How does a BJT act as a switch? A transistor has three modes: active region, cut off region and the saturation region. The transistor acts as a switch in the cut-off mode and the saturation mode. The transistor is fully off in the cutoff region and fully on the saturation region.
What separate the three regions in a BJT?
The regions of a BJT are called emitter, base, and collector. A discrete transistor has three leads for connection to these regions.
Why does a variable resistor work?
A variable resistor works by adjusting the path that current has to flow. The dial you turn will move another piece of wire inside the resistor. The end result is that the electricity will travel through a certain length of the strip depending on where you turn the knob.
What is a variable resistor called?
A variable resistor is a resistor of which the electric resistance value can be adjusted. These resistors are called digital potentiometers.
What are regions of BJT?
A bipolar junction transistor (BJT) has three operating regions:
- Cut off ( for NPN BJT)
- Active region ( for NPN)
- Saturated ( for NPN)
How many regions of BJT are there?
four
Regions of operation. Bipolar transistors have four distinct regions of operation, defined by BJT junction biases. The base–emitter junction is forward biased and the base–collector junction is reverse biased.
Is a transistor a resistor?
A transistor is like a resistor, except that the resistor can be controlled by a second input called base input; It should also be noted that the gate input of the transistors is the transmitter and the output is the collector (its backward reason).
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