Rectifiers and Smoothed DC Supplies

Question 1

What are the 2 major classes of power supplies?

Answer 1

Linear Supplies
Switched Mode Supplies

Question 2

Define Rectification

Answer 2

Converting an AC current to a DC

Question 3

Explain the process of a half wave rectifier (including a capacitor)

Answer 3

-The diode conducts in the positive half of the cycle
-negative half is reverse bias so AC source does not drive circuit
-During positive half, capacitor conducts and discharges in negative half cycle
-voltage drop across the load due to capacitors stored charge

Question 4

Explain the process of full wave rectifier

Answer 4

-A full wave rectifier can drive the load in both halves of the cycle.
-Current passes two diodes at a time
-The capacitor only discharges for half a cycle before it is charged again
-Therefore, there is a lower voltage drop and lower ripple voltage

Question 5

What does a smaller ripple voltage mean?

Answer 5

A smoother voltage output

Question 6

Why is there a difference in voltage across the circuit and the load (non-ideal diode)

Answer 6

The forward voltage of the diode causes a voltage drop across the load which is usually between 0.5-0.7V