Welcome to Professor MAD.
Electronics for beginners.
Today we are going to study about,
Direct Current (DC) & Alternating Current (AC).
We know moving electron flow can be known as a current.
We can convert the energy of moving electrons to do work.
This is a conductor.
In conductor outer electrons of the atoms are loosely bound,
and free to move through the material.
Let's apply a voltage difference to two ends.
The electrons start to move from low voltage to high voltage.
Since electrons have negative charges, this is a negative charge flow.
Negative charge flow can be known as a negative current.
A light-bulb can convert the energy of moving electrons into work.
Here the electron flow only moves in one direction.
So we call it as a direct current flow.
In short form DC.
What happens if we change the polarity of voltage?
Electrons eventually slow down and start to move in opposite direction,
because electrons always flow from low voltage to high voltage.
Let's change the polarity again.
Again.
And again.
Let's do it more frequently.
Electrons are moving back and forth.
They are alternating.
This kind of electron flow can be known as an alternating electron flow.
An alternating current.
The light-bulb is still working .
No matter what Direct current or Alternating current,
we can harness the movement of electrons to do work.
Pay attention to the voltage at one end.
It goes up and then comes to zero,
and goes down and the again becomes zero.
This cycle repeats again and again.
Let's draw a voltage time graph,
for the one end of the conductor.
Voltage goes up and then comes to zero,
and goes down and again becomes zero
This cycle repeats again and again.
This is a simple cycle.
This graph is identical to the sine wave graph.
In direct current flow electrons are moving in constant speed to one direction.
But in alternating current electrons oscillate back and forth.
Number of oscillations per second is called as the frequency.
That's how we derive the graph of AC and DC.