Transistors Lecture Notes

Flashcards generated from lecture notes on transistors.

Base Region

Region in transistor with moderate doping concentration.

Emitter function

The function formed in between emitter and base.

Emitter Region

Region in transistor where doping concentration is very low.

Emitter Region

Is denoted with the letter 'E'.

Base Region

Region in transistor that controls the flow of charge carriers.

Base Region

The region contained the flow of charge carriers.

Collector function

Function formed in between base and collector junction.

Base Region

Transistor is denoted by 'B'.

Collector Region

The size of the collector region is very large, with the function collected charge carries and is moderately doped.

Collector function

The function formed in between the base-collector.

Emitter, base, and collector

The three regions that transistors consist of.

Transistor

A semiconductor device which controls and amplifies electrical signals.

Emitter function and collector function

Functions formed in between emitter, collector, and base.

N-P-N transistor

A type of transistor formed by sandwiching P-type semiconductor between N-type semiconductors.

P-N-P transistor

A transistor is sandwiched N-type between P-type semiconductors.

Active region mode

The mode of operation when the emitter junction is forward biased and the collector junction is reverse biased.

Inverted mode

Mode of operation is when emmitter junction is reverse biased and the collector junction is forward.

Saturation mode

Mode of operation is when both the emitter and collector junctions are forward biased

Cut off operation

Mode of operation is when both the emitter and collector junctions are reverse biased.

Transistor Analysis

Analyzing the working of NPN transistors when the transistor is operated on active region mode.

NPN Transistor Charge

When the transistor is N-P-N, the majority charge carriers within the emitter region are electrons which are repelled by the negative terminal.

Electron flow in Transistor

In the NPN transistor, the electrons in transit into the collector junction which is reversed biased and attracted to the battery.

Collector current

The current produced due to electrons emitted from the emitter region and connecting on the collector region.

Transistor Configuration

Transistor amplifier or circuit is onfiguration is common base, common emitter, and common collector.

Input and Output Determination

Input and output signal relationships can be determined through the circuit diagram. The emitter junction is forward biased.

Input Paremeters

Input parameters are base-emitter current and the base-emitter voltage.

Signal Relationships

A way to find input output signal relationships with a circuit diagram. The base emitter collector function is forward biased.

Output Characteristics

Output Voltage is typically constant and the emitter current is directly proportional to the emitter bias voltage.

Collector Junction

Output characteristics shift towards lower voltages and higher voltages.

Relationship Determination

To determine the input and output signal relationship circuit diagram, the base emitter junction is reverse biased.

Input and Output Parameters

The input parameter is base current and the output parameter is collector-emitter voltage.

Junction Behavior

Since the collector junction is reverse biased, the output voltage is determined primarily by the output characteristics of that junction.

Transistor Operation

A transistor is selected for application purposes and operated on active region mode.

Input Impedance

Input Impedance h(ie) is the ratio of change in input voltage to the corresponding change in input current at constant output voltage.

Output Admittance

Output admittance h(oe) is the ratio of change in output current to the change in output voltage at constant input current.

Current Transfer Ratio

Current transfer ratio h(fe) is a ratio of change in output current to the corresponding change in input current and constant voltage.

Voltage Feedback Ratio

Voltage feedback ratio h(re) is ratio of change in input voltage to change in output voltage at constant input current.

Circuit Diagram

Circuit diagram is used to show DC configuration in Common Emitter Configuration.

Input Parameters

Input parameters are the total DC bias voltages.

Diode

Base-Emitter voltage is set for forward biasing the transistor.

Voltage

Change of input characteristics is maintained with constant voltage.

Operation

The output current is nearly independent of both input current and collector-emitter voltage.

Input Resistance (hie)

The input resistance is equal to the change in base-emitter voltage divided by the change in base current, with a constant collector-emitter voltage.

Output Admittance (hoe)

The output admittance is equal to the change in collector current divided by the change in collector-emitter voltage, with a constant base current.

Forward Current Gain (hfc)

The forward current gain is equal to the change in collector current divided by the change in base current, with a constant collector-emitter voltage.

Reverse Current Gain (hrc)

The reverse current gain is equal to the change in base-emitter voltage divided by the change in collector-emitter voltage, with a constant base current.