Alternating Current

What is Ireland’s standard AC frequency?

50 Hz

What is the formula to find voltage

a)RMS Value

b) Average Value

a) RMS = Vpeak x 0.707

b) Avg = Vpeak x 0.637

Convert a peak voltage of 325V to RMS and average values.

RMS (Root Mean Square) (constant of 0.707) = 230V = (325v × 0.707)

Average = 207V = (325V x 0.637)

Why does a capacitor block DC but allow AC?

DC charges it once; AC continuously charges/discharges it.

What is inductive reactance (Xl)

Opposition to AC current in inductors

(Xl) = 2πfL

Xl = Inductive Reactance in Ω

f = frequency in Hz = 50Hz Ireland

L = inductance in Henry’s (H)

What is the Capacitive Reactance (Xc)

Opposition to AC current in Capacitors

Xc = 1/2πfC

Xc = Capacitive Reactance

f = frequency of AC signal (Hz)

C = Capacitance in Farad (F)

A 50Hz AC circuit has a 0.1H inductor.

Calculate Xl

Xl = 2πfL = 2π x 50 × 0.1 = 31.4Ω