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21. Alternating currents

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  1. 21.1 Characteristics of alternating currents

    1. • understand and use the terms period, frequency and peak value as applied to an alternating current or voltage

    2. • use equations of the form x = x0 sin ωt representing a sinusoidally alternating current or voltage

    3. • recall and use the fact that the mean power in a resistive load is half the maximum power for a sinusoidal alternating current

    4. • distinguish between root-mean-square (r.m.s.) and peak values and recall and use I r.m.s. = I0 / sqrt(2) and Vr.m.s. = V0 / sqrt(2) for a sinusoidal alternating current

  2. 21.2 Rectification and smoothing

    1. 21.2.1Distinguish graphically between half-wave and full-wave rectification

      • distinguish graphically between half-wave and full-wave rectification

    2. 21.2.2The use of a single diode for the half-wave rectification of an alternating

      • explain the use of a single diode for the half-wave rectification of an alternating current

    3. 21.2.3The use of four diodes (bridge rectifier) for the full-wave rectification of

      • explain the use of four diodes (bridge rectifier) for the full-wave rectification of an alternating current

    4. 21.2.4The effect of a single capacitor in smoothing

      • analyse the effect of a single capacitor in smoothing, including the effect of the values of capacitance and the load resistance