# Types of current waveforms & Features Of A.C. Waveform

Show/Hide Sub-topics (Alternating Current | A Level)

Direct current means that the polarity of the e.m.f remains constant with time.

• Current flows only in one direction, hence charge carriers flow in one direction only.

Types of direct current waveforms:

Alternating current means that the polarity of the e.m.f. changes with time.

• Direction of current flow in the electrical circuits varies with time in a periodic manner.
• Direction of the charge carriers’ flow changes back and forth.

Types of alternating current waveforms:

### Features Of An A.C. Waveform

The sinusoidal alternating current can be represented by $I = I_{o} \, sin \, \omega t$

For a I vs T graph,

• A cycle refers to one complete alternation of $I$
• Period T refers to the time taken to complete one cycle of variation
• Frequency f is the number of complete cycles of variation in one second
• Instantaneous current refers to the current value at an instant of time.
• Peak current value $I_{o}$ refers to the maximum current during the cycle or the amplitude of the a.c. signal.
• Peak to peak value is the difference between the positive and negative $I_{o}$ value. For sinusoidal a.c., the peak to peak value is 2 $I_{o}$.