Advanced Analog Circuits Seth Price Department of Chemical Engineering New Mexico Tech Rev. 1/26/15

Diodes (PN Junction) Diodes conduct in only one direction Semiconducting device Resistance is non-linear Require a “knee” or “turn-on” voltage – Silicon: V – Germanium: 0.3V – LED: 1.7V

Diode Vs. Sine Wave content/uploads/2009/08/23-half-wave-rectifier-1024x368.gif

IV Curve for Diodes

Zener Diode Diode that is meant to operate in reverse bias region – Very stable, consistent voltage Can be used to replace battery, complex resistor network in some situations

Capacitors Store energy in an electric field Measured in Farads (F) Two physical configurations – Parallel plates – Concentric cylinders

Capacitor Combinations Series Combination: 1/C eq = 1/C 1 + 1/C 2 + … + 1/C n Parallel Combination: C eq = C 1 + C 2 + … + C n

Capacitor Voltage Vc(t): Voltage across capacitor at any time Vs: Source voltage T: Time constant t: elapsed time V c(t) = V s (1-e -t/T )

Inductors Store energy in a magnetic field Measured in Henries (H) Typically a coil of wire Adjustable inductor: slug

Inductor Combinations Series Combinations L eq = L 1 + L 2 + … + L n Parallel Combinations 1/L eq = 1/L 1 + 1/L 2 + … + 1/L n

Inductor Voltage V(t): Voltage across Inductor as a function of time L: inductance in Henries di/dt: change in current with respect to time V(t) = -L * di/dt

Time Constants Time Constant (T): way to characterize time to charge/discharge a capacitor or inductor 1*T: 63% of the maximum charge 5*T: fully charged For a capacitor: T = R*C For an inductor: T = L/R

Solenoids Changing current induces magnetic field Magnetic field moves plunger Used in starter motors, valves, latches, etc.

Solenoid Valve

Transformers Two adjacent inductors that can influence each other Can add an iron core to transformer to increase magnetic field No electron travels between inductors – Isolation Transformer

Transistors Semiconducting device Used as switches, amplifiers, attenuators, impedance matching, etc. Two major categories (NPN, PNP) Types: BJT, MOSFET, JFET, etc.

Putting it all together… DC Power Supply