What is Transistor | Definition | Principle | Properties

What is Transistor ? When a third doped element is added to a crystal diode in such a way that two pn junctions are formed, the resulting device is known as a transistor. The transistor—an entirely new type of electronic device—is capable of achieving amplification of weak signals in a fashion comparable and often superior … Read more

Common Base Connection | Transistor Connections

What are Transistor Connections There are three leads in a transistor viz., emitter, base and collector terminals. However, when atransistor is to be connected in a circuit, we require four terminals; two for the input and two for the output. This difficulty is overcome by making one terminal of the transistor common to both input … Read more

Common Emitter | Common Collector Connection

What is Common Emitter? In this circuit arrangement, input is applied between base and emitter and output is taken from thecollector and emitter. Here, emitter of the transistor is common to both input and output circuits and hence the name common emitter connection. Fig. 8.16 (i) shows common emitter npn transistor circuit whereas Fig. 8.16 … Read more

Transistor Load Line Analysis | Operating Point

Comparison of Transistor Connections The comparison of various characteristics of the three connections is given below in the tabularform. The following points are worth noting about transistor arrangements : Common Base Circuit The input resistance (ri) of CB circuit is low because IE is high. The output resistance (ro ) is high because of reverse … Read more

Cut off and Saturation Points | Power Rating of Transistor

What is Cut off and Saturation Points Fig. 8.49 (i) shows CE transistor circuit while Fig. 8.49 (ii) shows the output characteristcs along with the d.c. load line. (i) Cut off The point where the load line intersects the IB = 0 curve is known as cut off. At this point, IB = 0 and … Read more

Transistor Testing | Transistor Lead Identification

Transistor Testing An ohmmeter can be used for the transistor testing i.e., whether the transistor is good or not. We know that base-emitter junction of a transistor is forward biased while collector-base junction is reverse biased. Therefore, forward biased base-emitter junction should have low resistance and reverse biased collector-base junction should register a much higher … Read more

Transistor Biasing | Faithful Amplification

Introduction Of Transistor Biasing The basic function of transistor is to do amplification. The weak signal is given to the base of thetransistor and amplified output is obtained in the collector circuit. One important requirement during amplification is that only the magnitude of the signal should increase and there should be no change in signal … Read more

Base Resistor Biasing | Methods of Transistor Biasing

What Are Methods Of Transistor Biasing? In the transistor amplifier circuits drawn so far biasing was done with the aid of a battery VBB which was separate from the battery VCC used in the output circuit. However, in the interest of simplicity and economy, it is desirable that transistor circuit should have a single source … Read more

Emitter Bias | Circuits | Examples Of Emitter Bias

What is Emitter Bias Circuit Fig. 9.15 shows the emitter bias circuit. This circuit differs from base-bias circuit in two importantrespects. First, it uses two separate d.c. voltage sources ; one positive (+ VCC) and the other negative (– VEE). Normally, the two supply voltages will be equal. For example, if VCC = + 20V … Read more

Voltage Divider Bias Method

What Is Voltage Divider Bias Method Voltage Divider Bias is the most widely used method of providing biasing and stabilization to a transistor. In this method, two resistances R1 and R2 are connected across the supply voltage VCC (See Fig. 9.24) and provide biasing. The emitter resistance RE provides stabilization. The name ‘‘voltage divider’’ comes … Read more