Lesson 3 - Diode Theory & Rectification Quiz

What happens in forward bias for a silicon diode?

• Current is blocked completely

• Diode starts conducting once threshold is reached

• It behaves like a resistor

• It emits light

What is reverse bias?

• Anode positive, current flows

• Cathode positive, current blocked

• Diode destroyed instantly

• Same as forward bias

What is the approximate forward voltage drop for a silicon diode?

• 0.1 V

• 0.3 V

• 0.7 V

• 1.2 V

In a half-wave rectifier circuit, what part of the AC waveform is passed?

• Both positive and negative halves

• Only the negative half

• Only the positive half

• Neither half

What does the DC output from a half-wave rectifier look like?

• Smooth constant DC

• Pulsed DC (gaps)

• Pure AC sine wave

• Square wave

Which of these is a common rectifier diode?

• 1N4148

• LED

• 1N4001

• Zener

What effect does adding a capacitor (filter) have to a rectified output?

• Increases ripple

• Smooths the output ⇒ reduces ripple

• Changes waveform to pure AC

• Blocks DC

How is average DC voltage (Vdc) of a half-wave rectified sine related to peak voltage (Vp)?

• Vdc ≈ 0.5 × Vp

• Vdc ≈ 0.707 × Vp

• Vdc ≈ 0.318 × Vp

• Vdc ≈ 1.273 × Vp

What could cause a measured DC voltage to be lower than theoretical in a rectifier circuit?

• Diode voltage drop

• Inaccurate oscilloscope calibration

• Ripple under load

• All of the above

Why is diode polarity important?

• To show which side lights up

• To ensure current flows only when expected

• To make the circuit look correct

• Polarity doesn’t matter