AET710-Transistors

If the current gain equals to 150. Find the base current IB when the collector current IC equals to 5.5mA.

B=IC/IB IB=5.5/150 IB=0.037mA

Current Gain

Beta, β

Current and Voltage Gain of (Common Emitter Configuration)

Both current and voltage gain can be described as medium, but the output is the inverse of the input, i.e. 180° phase change.

Bipolar Transistor Configurations

Common Base Configuration Common Emitter Configuration Common Collector Configuration

1. Name the type and the configuration of component 4 that is used in the circuit.

Common base configuration.

Identify the numbered components and its function in given circuit application

Component # Name Function 1 Light Dependent Resistor (LDR) # component that has a (variable) resistance that changes with the light intensity that falls upon it. # The LDR has maximum resistance when it is exposed to darkness, and the voltage drop across it is sufficient to turn ON the transistor. This in turn switches ON the LED. #When a LDR is kept in the dark place, its resistance is high and, when the LDR is kept in the light its resistance will decrease. 2 Resistor to control the flow of current to other components. 3 Light Emitting Diode (LED) It is a semiconductor device that emits visible light when an electric current passes through it. 4 Transistor It is a semiconductor device used to amplify or switch electronic signals and electrical power.

Single Stage Amplifier Circuit(Class A power amplifier circuit)

Explain the input and the output signal from the simulation circuit on multisim

If the transistor has a DC current gain, (Beta) of 120. Calculate the collector current IC if the input voltage will produce base current IB of 30μA.

IB=IC /β IC=IB ×β=55×10-6 ×120 IC= 6.6 mA

Current Gain

IC/IE is the current gain

Calculate the emitter current, IE.

IE=IB + IC IE=0.037+150=150.037mA

Calculate the emitter current, IE

IE=IC +IB IE= 6.6 mA + 0.055 mA IE= 6.655 mA

1. Explain the operation of component 4 in the digital given circuit in details.

In the given circuit , component 4 , which is a transistor, acts as a switch. When LDR is exposed to light , its resistance decreases and all current flows to ground. When LDR in darkness , its resistance increases and current flows to base of transistor activating it. When transistor is activated , current flows between Collector and Emitter and LED light up.

Saturation Region

In this mode of operation, both the emitter base and collector base junctions are forward biased. Current flows freely from collector to emitter when the base-emitter voltage is high. In this mode device is fully switched ON.

Active Mode

In this mode transistor is generally used as a current amplifier. In active mode, two junctions are differently biased that means emitter-base junction is forward biased whereas collector-base junction is reverse biased. In this mode current flows between emitter and collector and amount of current flow is proportional to the base current.

Cut-off Region

In this mode, both collector base junction and emitter base junction are reverse biased. This in turn not allows the current to flow from collector to emitter when the base-emitter voltage is low. In this mode device is completely switched off as the result the current flowing through the device is zero.

single-stage amplifier

Name the type and the configuration of the BJT that is used in the circuit.

Explain why (CE) configuration is the most commonly used circuit for transistor based amplifiers?

The common emitter amplifier configuration produces the highest current and power gain of all the three bipolar transistor configurations

The Common Base (CB) Configuration

The input signal is applied between the transistors base and the emitter terminals while the corresponding output signal is taken from between the base and the collector terminal The base terminal is grounded or can be connected to some fixed reference voltage point. IE = IC + IB

What is the main function of the circuit above?

The main function is amplifying the input signal (amplifier)

2.1 Basics of Bipolar Junction Transistors (BJTs)

These three terminals are known and labelled as the Emitter (E), the Base (B) and the Collector (C) respectively

Explain the operation of the transistor in the analog given circuit in details.

Transistor worked as a amplifier

Transistors

Transistors are three terminal active devices made from different semiconductor materials

Identify the type of the BJT used in the circuit above:

What is the configuration of the BJT that is used in the circuit?

The Common Collector (CC) Configuration

the collector is connected to ground through the supply The input signal is connected directly to the base terminal the output signal is taken from across the emitter load resistor

The Common Emitter (CE) Configuration

the input signal is applied between the base and the emitter the output is taken from between the collector and the emitter

Explain the current and Voltage Gain for CB

voltage gain is high current gain is low