Transistor Biasing and Differential Amplifiers

These flashcards cover key concepts from the lecture about transistor biasing, small signal modeling, and differential amplifiers.

Transistor Load Line Analysis

A method used to plot output characteristics of a transistor to determine collector current and collector-emitter voltage.

Operating Point (Q-point)

The intersection point of the load line and the output characteristics curve, representing the stable DC operating condition of the transistor.

Transistor Biasing

The process of establishing a proper flow of zero signal collector current and maintaining the appropriate collector-emitter voltage during signal passage.

Types of Biasing Circuits

The four types include: Base Bias, Emitter Bias, Collector Biasing with feedback resistor, and Voltage Divider Biasing.

Base Bias (Fixed Biasing)

A biasing method where a base resistor is connected between the power supply and base of the transistor.

Emitter Biasing

A biasing method that connects a resistance to the emitter terminal, also including a base resistor between base and power supply.

Collector Biasing

A biasing method where a feedback resistor from collector to base controls base current.

Voltage Divider Biasing

A widely used biasing method that employs resistors to stabilize the operating point against variations in transistor parameters.

Common-Mode Rejection Ratio (CMRR)

A measure of an amplifier's ability to reject common-mode signals, defined as the ratio of differential voltage gain to common-mode gain.

Small Signal Model of BJT

A representation of a BJT under small signal conditions, often implemented with Hybrid-Π and T-models.

Differential Amplifier

An amplifier that produces output based on the difference between two input signals, with common-mode and differential operational modes.

Hybrid-Π Model

A small signal model that includes transconductance and output resistance for representing BJT behavior.

Logic Gates using BJT

Transistors can be configured to function as different logic gates - NOT, AND, OR, NAND, etc.

Differential Inputs Configuration

When two opposite-polarity signals are applied to the inputs of a differential amplifier.

Single-Ended Differential Input

A configuration where one input is grounded and the signal voltage is applied only to the other input.

Common Mode Inputs

A condition where equal phase signals are applied to both inputs of a differential amplifier.