AC CIRCUITS | LECTURE 1

waveform

is a plot of values (i.e. voltage (v) or current (i)) of quantities which vary

with time (t).

> Instantenous value

> Peak Value

> Peak to peak value

A waveform can be characterized by the following values

Instantaneous Value (if voltage, v(t))

- the magnitude of a waveform at any instant of

time

Peak Value (e.g. for voltage, Vp)

the maximum (or minimum, depending on context)

instantaneous value of a function from the zero-volt level

Peak-to-peak Value (e.g. for voltage, Vp-p)

- the magnitude between the positive and

negative peaks

Periodic Waveform

repeats the exact shape repeatedly. It can be represented as a signal that

satisfies the following equation:

Period (T)

the time interval between successive repetitions of a periodic waveform

Cycle

- the portion of a waveform contained in one period

Frequency (f)

the number of cycles that occur in one second

sinusoidal waveforms

In the context of Electrical Engineering, particularly for Alternating Circuit (AC) systems, we

primarily deal with periodic ***** ***** for both voltage and current.

> Average Value (Vave, Iave)

> Root-Mean-Square (RMS) Value (Vrms, Irms)

While we can already represent a sinusoidal waveform simply by its maximum value, in

general sinusoidal electrical parameters are instead represented by its:

0

Average Value for sinusoidal

x/sqr2

RMS value for sinusoidal

A

The general format of a sinusoidal waveform is:

positive

A ****** phase shifts the waveform to the left:

negative

On the other hand, a ***** phase shifts the waveform to the right:

TRIGONOMETRIC PROPERTIES

phasors

In electrical engineering, **** are utilized iIn order to have an easier representation of the

periodic waveforms

Xi = wL

INDUCTOR (Xi) value?

Xc = 1/wC

CONDUCTOR (Xc) Value?

2pif

angular frequency (w) value?

Inductor

Volts Lead Current

conductor

Current Leads Volts

Capacitance (C), Farad (f)

Sign for Capacitor

Inductor (L), Henry (H)

Sign for Inductor?

pi/2

0 value

phi = phi 1 - phi 2

Phase Relationship for angular

TRUE! FOLLOW THIS

phi = radian (180/pi) Ex. xt = 5t(180/pi) | True of False?