Bjt Output Characteristics

December 21, 2023 Post a Comment

Bjt output characteristics

Two terms that you must remember: Input characteristic – the variation of the base current (IB) with the base-emitter voltage (VBE) Output characteristic – the variation of the collector current (IC) with the collector-emitter voltage (VCE)

What is the main characteristics of BJT?

A bipolar junction transistor is a three-terminal semiconductor device that consists of two p-n junctions which are able to amplify or magnify a signal. It is a current controlled device. The three terminals of the BJT are the base, the collector, and the emitter.

What are the output characteristics?

Output characteristics : It is the graph drawn between output current and output voltage when input current is kept constant.

What are output characteristics of transistor?

Output Characteristics: The curve is obtained by plotting the output current against output voltage keeping the input current constant. Current Transfer Characteristics: This characteristic curve describes the variation of output current in accordance with the input current, keeping the output voltage constant.

Why BJT is called bipolar?

Simply put, a BJT is a three-terminal semiconductor device. The name "bipolar" comes from the fact that this type of transistor contains two types of semiconductor material—one positive type (p-type) and one negative type (n-type)—through which a current flows. Bipolar junction transistors usually contain silicon.

Why BJT is called bipolar device?

Bipolar transistors are a type of transistor composed of pn junctions, which are also called bipolar junction transistors (BJTs). Whereas a field-effect transistor is a unipolar device, a bipolar transistor is so named because its operation involves two kinds of charge carriers, holes and electrons.

What is the working principle of BJT?

Working Principle of BJT The emitter-base junction of BJT is forward-biased, whereas the collector-base junction is reverse biased. The forward bias of the emitter-base junction causes the emitter current to flow and this emitter current entirely flows in the collector circuit.

What is the transfer characteristic of BJT?

In BJTs or bipolar transistors, transfer characteristics can be understood as plotting of an output current against an input-controlling magnitude, which consequently exhibits a direct “transfer” of variables from input to output in the curve represented in the graph.

What is the function of BJT?

As with all transistors, the basic function of a BJT is typically to function as a switch or to amplify, filter, and rectify power. Bipolar transistors are current-controlled and operated devices, meaning that a much smaller base current causes a larger current to flow from emitter to collector.

What is the output of transistor?

A transistor can use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals. This property is called gain. It can produce a stronger output signal, a voltage or current, which is proportional to a weaker input signal and thus, it can act as an amplifier.

What is output voltage in transistor?

So under typical circumstances, there is a ~0.7V drop from the base to the emitter. In other words, the voltage at the top of R1 will be about 0.7V less than the voltage at the top of R2.

What is output characteristics of common base configuration?

What is the output characteristics of common base configuration? The variation of collector current IC with the collector-base voltage (VCB ) at constant emitter current (IE ) is called output characteristics of the transistor in the common base configuration. It can be written as Ic = F (VCB, Ic ).

What is input resistance of BJT?

AC input resistance of the transistor = dVbe/dIb = re(1 + beta) where re = dVbe/dIe = 25mV/Ie (at 25 degreesC). re is the intrinsic emitter resistance otherwise known as the dynamic emitter resistance. AC input resistance of complete circuit = Rin + re(1 + beta).

What are the 3 configuration of transistor?

The three types of configurations are Common Base, Common Emitter and Common Collector configurations.

What are the different configuration of BJT?

The three basic configurations of a BJT are (a) common emitter (CE), (b) common base (CB), (c) common collector (CC) or emitter follower. These basic configurations are shown in Figure 1.

Why BJT is used as 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. Because a transistor's collector current is proportionally limited by its base current, it can be used as a sort of current-controlled switch.

How BJT is current-controlled?

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).

Is BJT bidirectional?

TRIAC allows the current in both directions and thus it is bidirectional. SCR, GTO (Gate Turnoff Thyristor) and BJT allow the current in only one direction.

Why BJT is current control device?

BJT is a current controlled device because the output characteristics of BJT are determined by the input current. In a p-n junction i.e base-emitter junction in BJT the change in voltage (Vbe) is produced only after the change in base current.

What is alpha and beta in BJT?

$\alpha $ is defined as the ratio of the collector current to the emitter current. \[~\alpha =\dfrac{{{I}_{C}}}{{{I}_{E}}}\] $\beta $ is defined as the current gain which is given by the ratio of the collector current to the base current.