About AC and DC circuits.

1. AC and DC Circuits

2. Ac current and Dc current
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3. Types of current
Alternating current(AC)
• AC changes the direction
continually
• In ac, the terminals of the source
of potential difference are
constantly changing sign. So,
there is no net motion of the
charge carriers, they simply vibrate
back and forth rapidly.
Direct current(DC)
• DC does not change the direction,
it moves in only one direction
• In dc, charges move in only one
direction with negative charges
moving from a lower to higher
electric potential. Hence
conventional current is directed
from the positive terminal to the
negative terminal of a battery.

4. • Alternating current is cheaper to generate and has fewer energy losses
than direct current when transmitting electricity over long distances. For
this reason, the current supplied to your home by power companies is ac
rather than dc.
• Batteries, solar cells etc produce dc.
• Power plants generates ac

5. Dc circuit
• The closed path in which direct current flows that is known as dc
circuit.
• Current flows only in one direction

6. AC Circuit
• AC circuits are simply circuits powered by an alternating source, either voltage or
current.
• An alternating current or voltage is one in which the value of either the voltage or the
current varies about a particular mean value and reverses direction periodically.

7. • In an AC circuit, the value of the magnitude and the direction of current and voltages is
not constant, it changes at a regular interval of time.
• It travels as a sinusoidal wave completing one cycle as half positive and half negative
cycle and is a function of time or angle.
• Similarly, the direction of the current is changed and the magnitude of current changes
with time it is called alternating current.

8. When an alternating voltage source is connected across a load resistance as shown in the figure
below, the current through it flows in one direction and then in the opposite direction when the
polarity is reversed.
• https://youtu.be/jIrHkRJVK-U

9. The waveform of the alternating voltage with respect to the time and the current flowing
through the resistance (R) in the circuit is shown below.

10. The various terms which are frequently used in an AC circuit are as follows
Amplitude
The maximum positive or negative value attained by an alternating quantity in one complete
cycle is called Amplitude or peak value or maximum value.
Alternation
One-half cycle is termed as alternation. An alternation span is of 180 degrees electrical.
Cycle
When one set of positive and negative values completes by an alternating quantity or it goes
through 360 degrees electrical, it is said to have one complete Cycle.
Instantaneous Value
The value of voltage or current at any instant of time is called an instantaneous value.

11. Frequency
The number of cycles made per second by an alternating quantity is called frequency. It
is measured in cycle per second (c/s) or hertz (Hz) and is denoted by (f).
Time Period
The time taken in seconds by a voltage or a current to complete one cycle is called Time
Period. It is denoted by (T).
Wave Form
The shape obtained by plotting the instantaneous values of an alternating quantity such
as voltage and current along the y-axis and the time (t) or angle (θ=wt) along the x-axis
is called a waveform.

12. AC and DC circuit differences
Difference between AC and DC circuit lies in the direction in which the electrons flow.
In DC circuits, current flows in one direction.
In AC circuits, current switches directions, sometimes going forward and sometimes
going backward