Which regions is a BJT used as a switch?

Which regions is a BJT used as a switch?

The transistor can be used as a switch if biased in the saturation and cut-off regions. This allows current to flow (or not) in other parts of a circuit.

What is the main reason that the BJT does not behave as an ideal current source in active region?

Because it is not made from ideal or non-ideal circuit elements. It is made by p-n junctions. So, if you use it with a voltage source as the base source, it will dependently be voltage-controlled.

In which condition does BJT behave like a closed switch?

Explanation: From the saturation mode characteristics, the transistor acts as a single pole single throw solid state switch. A zero collector current flows. With a positive signal applied to the base of transistor it turns on like a closed switch.

Why inverse active mode of transistor is not useful?

The downside to reverse active mode is the β (βR in this case) is much smaller. To put a transistor in reverse active mode, the emitter voltage must be greater than the base, which must be greater than the collector (VBE<0 and VBC>0). Reverse active mode isn’t usually a state in which you want to drive a transistor.

What is the condition for BJT to operate 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. In this region, I C almost remains constant for a given value of I B. But as V CE increases, I C increases slightly since the base-collector depletion region widens.

Can BJT be used as a switch?

So lets get started with BJT as Switch. In the below figure the circuit shown explains the operation of BJT as a switch. In the first circuit, the transistor is in the cutoff region because the emitter-base junction is not forward biased condition.

What is a bipolar junction transistor (BJT)?

Bipolar junction transistors (Also known as BJTs) can be used as an amplifier, filter, rectifier, oscillator, or even a switch, which we cover an example in the first section. The transistor will operate as an amplifier or other linear circuit if the transistor is biased into the linear region. The transistor can be used as a switch

How does a BJT work in the saturation region?

Figure 8. An npn BJT operating in the saturation region acts like a closed switch. For a BJT to operate in the saturation region, the base-emitter junction and base-collector junction should be forward-biased, and there should be a sufficient base current to produce the collector saturation current, I C (sat).