_lab config tables

Related Concepts: complementary power amplifier | JFET Voltage Amplifier | MOSFET Voltage Amplifier

Experiment/Circuit Configuration	Theories	Voltage Gain ( $A_v$ )	Current Gain ( $A_i$ )	Input Impedance ( $Z_i$ )	Output Impedance ( $Z_o$ )	Phase Relationship	Key Facts/Applications
Common Emitter (CE)	Emitter is common to both input and output. Base-emitter junction forward biased, collector-base reverse biased.	High ( $A_v>1$ or $\approx 200$ )	High (approx. $\beta$ value, e.g., $50$ to $100$ )	Medium ( $1000$ to $5000\Omega$ )	Medium ( $1000$ to $50,000\Omega$ ; typically approx. collector resistor value)	$180^{\circ }$ out of phase (Inverted)	Most widely used for voltage and current amplification; gain decreases with external load.
Common Collector (CC) / Emitter Follower	Collector is common to both input and output. Emitter voltage follows base voltage minus diode drop.	Less than unity (approx. $0.98$ to $1$ )	High (greater than unity; typical value about $50$ )	High ( $20\text{k}$ to $1000\text{k}\Omega$ )	Low ( $20$ to $1000\Omega$ )	In-phase ( $0^{\circ }$ shift)	Used as a Buffer or impedance matching device (high $Z$ source to low $Z$ load).
Darlington Pair	Two transistors connected such that the emitter of the first drives the base of the second.	Less than unity (operates as emitter follower)	Extremely High (product of individual betas: ${\beta }_1\times {\beta }_2$ )	Extremely High ( $Z_i\approx {\beta }_1{\beta }_2{R}_E$ )	Very Low	In-phase ( $0^{\circ }$ shift)	Used for measuring weak currents or high-impedance sensors; massive total current gain.
JFET Voltage Amplifier	Voltage-controlled device using an electric field to pinch off the channel. Gate is reverse biased.	Moderate (dependent on transconductance $g_m$ and load resistance)	Low ( $I_G=0$ , but current gain isn’t a primary metric)	Extremely High (almost no gate current)		$180^{\circ }$ out of phase (Common Source configuration)	Self-bias used for stability; used in high-impedance microphones and low-noise pre-amps.
MOSFET Voltage Amplifier	Gate insulated by ${\text{SiO}}_2$ ; depletion mode device can operate at zero bias.	Proportional to transconductance ( $g_m\times R_L$ )		Ultra-High (higher than JFET due to insulated gate)		$180^{\circ }$ out of phase (Common Source configuration)	Can swing both positive (Enhancement) and negative (Depletion) around $0\text{V}$ .
RC Coupling (Cascaded)	Two-stage amplifier connected via capacitors to block DC while passing AC.	Product of individual gains ( $A_{\text{total}}=A_1\times A_2$ )		Input impedance of stage $2$ acts as load on stage $1$		In-phase ( $360^{\circ }$ total shift from two CE stages)	Frequency response limited by coupling capacitors; flat response over audio range.
Complementary Power Amplifier (Class AB)	Push-Pull configuration using NPN and PNP transistors; biased to eliminate crossover distortion.	Less than unity (considered a voltage loss, approx. $0.30$ )			Relatively Low		Eliminates input/output transformers; high efficiency; NPN handles positive half, PNP handles negative.
Direct Coupling	Stages connected without capacitors, allowing low frequency and DC amplification.	Greater than transformer coupled, often less than RC coupled				Depends on stages (e.g., NPN driving PNP)	Excellent low-frequency response; sensitive to temperature-induced DC drift.