E6: Circuit Components
Subelement E6 covers the electronic components used in amateur radio equipment at the device level. Topics include semiconductor materials and transistor types (BJTs and FETs, including depletion and enhancement modes, alpha and beta, and MOSFET gate protection); diode types and their specific characteristics (Zener, Schottky, varactor, PIN, point-contact, and LEDs); digital IC families, comparators, tri-state logic, CMOS noise immunity, pull-up/pull-down resistors, and programmable logic; inductors and transformers including permeability, core materials, toroidal vs. solenoidal design, eddy current losses, piezoelectricity, and crystal equivalent circuits; RF-specific semiconductor materials and packaging (GaAs, GaN, MMICs, surface-mount vs. through-hole); and electro-optical devices including photoconductors, photovoltaic cells, optoisolators, optical encoders, and solid-state relays.
The Extra exam draws six questions from E6 — one from each group. Questions cover specific device characteristics, material properties, and the practical reasons for choosing one component type over another.
Study These Topics
E6A: Semiconductor Materials and Devices
N-type and P-type materials, donor and acceptor impurities, GaAs for microwave use, PN-junction reverse bias and depletion region, FET vs. BJT input impedance, beta definition, NPN biased-on voltage (0.6–0.7 V), alpha cutoff frequency, depletion-mode vs. enhancement-mode FETs, dual-gate MOSFET, and Zener diode MOSFET gate protection.
Study E6AE6B: Diodes
Zener diode constant voltage drop, Schottky diode lower forward voltage and metal-semiconductor junction, LED forward voltage from band gap, varactor as voltage-controlled capacitor, PIN diode RF switching via low junction capacitance and DC bias control, point-contact diodes as RF detectors, and junction failure from excessive temperature.
Study E6BE6C: Digital ICs
Comparator hysteresis prevents unstable output from noisy inputs, threshold crossing changes output state, tri-state logic adds high-impedance state, BiCMOS combines CMOS input impedance with bipolar output, CMOS lowest power consumption, CMOS noise immunity from half-supply threshold, pull-up/pull-down resistors, FPGA design with HDL, NAND/NOR/NOT gate symbols.
Study E6CE6D: Inductors and Piezoelectricity
Piezoelectricity generates voltage from stress and deformation from voltage, quartz crystal equivalent circuit (series RLC + shunt C), laminated cores reduce eddy currents, ferrite vs. powdered iron (ferrite fewer turns, powdered iron better temperature stability), permeability determines inductance, toroidal cores confine magnetic field, brass decreases inductance, ferrite beads as parasitic suppressors, inductor saturation from excessive flux.
Study E6DE6E: RF Semiconductors and Packaging
GaAs higher electron mobility at UHF, GaN for highest-frequency MMICs, MMIC characteristics (50 Ω I/O, controlled gain, low noise, microstrip connections, output-lead DC bias), DIP through-hole package definition, DIP unsuitable at UHF due to excessive lead length, surface-mount least parasitic effects, SMT advantages at RF.
Study E6EE6F: Electro-Optical Technology
Photovoltaic cells absorb light energy via electrons, efficiency = fraction of light converted to current, silicon is primary PV material, open-circuit voltage ≈ 0.5 V, photoconductive material resistance decreases with light, crystalline semiconductor for photoconductors, optoisolator = LED + phototransistor, electrical isolation for AC control, optical shaft encoder, solid-state relay.
Study E6FE6A: Semiconductor Materials and Devices →
← E5: Electrical Principles