sentences:  Portions include sinusoidal alternating quantities such as peak values, instantaneous values, RMS average values, phase; electrical resonance, and quality factor for radio circuits.The syllabus then moves on to semiconductors, specifically the construction and operation of valves, also known as vacuum tubes.Included in this portion of the syllabus are thermionic emissions with their characteristic curves, diodes, triodes and multi-electrode valves; and the use of valves as rectifiers, oscillators, amplifiers, detectors and frequency changers, stabilisation and smoothing.