Mathematics, Physics and Electrical Fundamentals
What you must understand
Mathematics: arithmetic and algebra (transposition of formulas), ratios and percentages, geometry (areas, volumes, circumference, Pythagoras), trigonometry (sine, cosine, tangent and their use in resolving vectors), and graphs. Physics: units and conversions (SI and imperial), mass versus weight, density, pressure (absolute versus gauge), work, power, energy, and the gas laws. Understand the relationship between force, area and pressure, and how a hydraulic system multiplies force.
Electrical fundamentals: Ohm's law, power law, series and parallel circuits, Kirchhoff's laws in simple form, resistance and temperature, capacitance and inductance at a conceptual level, AC and DC, frequency and RMS values, transformers, and the meaning of impedance. Understand the magnetic effect of current and how a relay or solenoid works.
Traps
Questions frequently mix gauge and absolute pressure, or ask for a result in different units. Another trap is a parallel circuit where candidates add resistances instead of using the reciprocal rule.
Worked example
Two 6 Ω resistors in parallel: 1/R = 1/6 + 1/6 = 1/3, so R = 3 Ω, not 12 Ω. For a hydraulic press, if a 100 N force acts on a 10 cm² piston, pressure is 10 N/cm²; acting on a 50 cm² piston it produces 500 N - force is multiplied, but the smaller piston must travel further.