Electrical Engineering, Electronics and Radio Theory
What you must know
This domain covers DC and AC circuit theory, Ohm's and Kirchhoff's laws, series and parallel combinations, power, reactance of inductors and capacitors, resonance, impedance, transformers, semiconductors (diodes, bipolar transistors, FETs), basic amplifier and oscillator principles, and digital logic basics. You should be fluent in decibels: power ratios, voltage ratios, dBm, and cascaded gains and losses. Also know the relationship between frequency, period and wavelength.
Typical traps
Mixed units (mA versus A, pF versus nF), RMS versus peak values, and the difference between power dB and voltage dB (factor 20 versus 10). Questions about resonance often hide a parallel-versus-series distinction: at resonance a series circuit has minimum impedance, a parallel circuit maximum. Another trap is assuming a transistor amplifies by itself: bias and operating point matter.
Worked example / rule of thumb
Two resistors of 100 Ω in parallel give 50 Ω; add a 50 Ω series resistor and the total is 100 Ω. For decibels: doubling power is +3 dB, halving is −3 dB, ten times is +10 dB. So a 5 W transmitter is about 7 dB above 1 W (10·log10 5 ≈ 7 dBW). Rule of thumb for cascaded stages: add gains and losses in dB directly. For wavelength, λ(m) ≈ 300 / f(MHz); 145 MHz gives about 2.07 m.
Exam technique
Write the formula first, substitute with units, then check plausibility: a result of 1 MW in a receiver front end signals an arithmetic slip.