Quick Answer: In Which Region Transistor Acts As A Switch?

In which region a transistor acts as an open switch?

Cutoff Region This is the region in which transistor tends to behave as an open switch.

The transistor has the effect of its collector and base being opened.

The collector, emitter and base currents are all zero in this mode of operation..

In which region BJT acts as a switch?

If the transistor is biased into the linear region, it will operate as an amplifier or other linear circuit, if biased alternately in the saturation and cut-off regions, then it is being used as a switch, allowing current to flow or not to flow in other parts of the circuit.

Which transistor is best for switching?

Best Transistors: BJTs#1 NPN – 2N3904. You can find most often NPN Transistors in low-side switch circuits. … #2 PNP – 2N3906. For high-side switch circuits, you need a PNP style BJT. … #3 Power – TIP120. … #4 N-Channel (Logic Level) – FQP30N06L.

Why BJT is called bipolar?

Bipolar transistors are called bipolar because the main flow of current through them takes place in two types of semiconductor material: P and N, as the main current goes from emitter to collector (or vice versa).

What is transistor gain?

bipolar transistors The current gain for the common-base configuration is defined as the change in collector current divided by the change in emitter current when the base-to-collector voltage is constant. Typical common-base current gain in a well-designed bipolar transistor is very close to unity.

How do transistors amplify?

A transistor acts as an amplifier by raising the strength of a weak signal. The DC bias voltage applied to the emitter base junction, makes it remain in forward biased condition. This forward bias is maintained regardless of the polarity of the signal.

Can transistor be used as rectifier?

A transistor can be used as a rectifier. When you connect base-emitter or base-collector region and use it as a diode, a transistor can work as a low current rectifier. It is just that standardrectifiers are cheaper and can rectify higher values of current as well, and hence, are preferred for rectification.

Why transistor is used as a switch?

When using the transistor as a switch, a small Base current controls a much larger Collector load current. When using transistors to switch inductive loads such as relays and solenoids, a “Flywheel Diode” is used. When large currents or voltages need to be controlled, Darlington Transistors can be used.

Which type of transistor is most commonly used?

The MOSFET is by far the most widely used transistor for both digital circuits as well as analog circuits, accounting for 99.9% of all transistors in the world. The bipolar junction transistor (BJT) was previously the most commonly used transistor during the 1950s to 1960s.

How do I choose the right transistor?

When choosing a transistor to use as a switch you need to consider its maximum collector current Ic(max) and its minimum current gain hFE(min). Transistor voltage ratings may be ignored for supply voltages less than 15V.

What is the symbol of BJT?

Unlike a normal p-n junction diode, this transistor has two p-n junctions. The basic symbols of BJT are n-type and p-type. Electronic current is conducted by both free electrons and holes in bipolar junction transistor.

How a transistor acts as a switch?

By turning a small input current into a large output current, the transistor acts like an amplifier. But it also acts like a switch at the same time. When there is no current to the base, little or no current flows between the collector and the emitter. … So the base current switches the whole transistor on and off.

When a transistor is used as a switch in what two states is it operated?

In an ideal switch, the transistor should be in only one of two states: off or on. The transistor is off when there’s no bias voltage or when the bias voltage is less than 0.7 V. The switch is on when the base is saturated so that collector current can flow without restriction.

What is PNP transistor?

The PNP Transistor is the exact opposite to the NPN Transistor device we looked at in the previous tutorial. … Then, PNP transistors use a small base current and a negative base voltage to control a much larger emitter-collector current.

What are types of transistor?

Types of transistorThere are two types of standard (bipolar junction) transistors, NPN and PNP, with different circuit symbols as shown. … The leads are labelled base (B), collector (C) and emitter (E). … In addition to bipolar junction transistors, there are field-effect transistors which are usually referred to as FETs.More items…

What is transistor diagram?

Diagram ‘A’ shows an NPN transistor which is often used as a type of switch. A small current or voltage at the base allows a larger voltage to flow through the other two leads (from the collector to the emitter). The circuit shown in diagram B is based on an NPN transistor.

Which is the fastest switching device?

MOSFETExplanation: MOSFET is the fastest switching device among the given four options.

When a transistor is saturated the collector current is maximum?

When the transistor operates in the Saturation then the voltage between collector and emitter terminal (Vce) is very low (typically it is 0.1 to 0.2 V), and the collector current Ic is maximum.