100+ Free EASA Module 4 Practice Questions

Diodes

Diode symbols and characteristics, the 0.7 V silicon barrier potential, forward and reverse bias, half-wave, full-wave and bridge rectifiers and ripple frequency, reservoir-capacitor smoothing, clippers and clampers, Zener voltage regulation, LED, thyristor (SCR) latching, Schottky, photodiode, varactor and varistor

Transistors

N-type and P-type doping, PNP/NPN construction and the IE = IC + IB relationship, common-emitter, common-base and emitter-follower configurations, potential-divider bias and stabilisation, emitter decoupling, negative feedback, amplifier classes A/B/C and crossover distortion, push-pull, oscillators, multivibrators, FETs and Darlington pairs

Integrated Circuits

Operational amplifiers (open-loop gain, virtual earth, inverting -Rf/Rin and non-inverting 1+Rf/Rg gain, voltage follower, comparator, integrator, differentiator, summing amplifier, slew rate) and digital logic gates (AND, OR, NOT, NAND, NOR, XOR), flip-flops and 5 V TTL levels

Printed Circuit Boards

PCB function and construction, etching copper-clad laminate, plated-through holes (vias) on multilayer boards, surface-mount versus through-hole components, and electrostatic-discharge precautions when handling MOS/CMOS devices

Servomechanisms

Open and closed loop control, error signal from comparison of demand and feedback, null-seeking action, follow-up systems, deadband, damping and velocity (rate) feedback from a tachogenerator, hunting from excess loop gain, and analogue transducers such as potentiometers and LVDTs

Synchro Systems

Torque transmitters (CX) and receivers, the three 120-degree stator windings, control transformers (CT) and the 90-degree null error voltage, differential synchros (CDX) for angle addition, resolvers and sine/cosine outputs, E and I transformers, capacitance transmitters, 26/115 V 400 Hz excitation, and lead-reversal and hunting defects