Power supplies, battery-powered devices, microcontroller circuits (Arduino, Raspberry Pi), consumer electronics, automotive systems.

Two input terminals (inverting '-' and non-inverting '+') and one output terminal.

Open-loop voltage gain: Differential gain in open-loop mode.
Input resistance: Resistance measured at either input terminal with the other grounded. ($R_{in}$)
Output resistance: Resistance measured at output with input source short-circuited. ($R_{out}$)
Bandwidth: Range of frequencies amplified almost equally.
Common-mode rejection ratio (CMRR): Ratio of differential gain to common-mode gain.
Slew rate: Maximum rate of change of output voltage per unit time.
Power supply rejection ratio (PSRR): Change in input offset voltage due to variation in supply voltage.
Input offset voltage: Output voltage for zero input (ideally zero, practically non-zero due to unbalances).
Input bias current: Average of currents flowing into input terminals.
Input offset current: Algebraic difference between input currents.

Output voltage is in phase with the input voltage.
Closed-loop gain ($A_{CL}$): $A_{CL} = 1 + \frac{R_f}{R_1}$ (for ideal op-amp)

Definition: A unipolar device where conduction depends on majority carriers.
Three terminals: Gate (G), Source (S), Drain (D).
Source is analogous to BJT Emitter, Gate to BJT Base, Drain to BJT Collector.