Alternate Current Flashcards
Whats the function of the laminated core?
To reduce energy loss due to heat by reducing induced/eddy currents in the core. This will decrease power loss due to joule heating.
Why is a soft iron core used?
To channel the magnetic field from the primary coil to the secondary coil through the core to increase flux linkage generated at the primary coil. This reduces the loss of magnetic flux linkage at the secondary coil.
What does an ideal transformer mean?
An ideal transformer is 100% efficient and has no power losses.
How is rectification acheived?
By using a rectifier such as the semi conductor diode
What is the function of the diode?
It allows current through itself in only one direction which is known as the forward bias direction.
How does a transformer work?
An alternating e.m.f. applied across the primary coil produces an alternating current in the primary coil.
This sets up a varying magnetic field which cuts the secondary coil due to the presence of the soft-iron core.
There will be a change in magnetic flux linkage in the secondary coil, and by Faraday’s law of electromagnetic induction, an alternating e.m.f. is induced across the secondary coil.
How to determine Irms from I2 -t graph?
Irms=
square root( Area under I2/ t graph for one period T)
Define root mean square if alternating current.
The root-mean-square (r.m.s.) value of an alternating current is the value of the steady current that will dissipate heat at the same average rate as the alternating current in a resistive load.
