Semiconductor diode I-V characteristics — practice questions

Question 1 · difficulty L1 · recall

A semiconductor diode conducts strongly when it is

• A. reverse biased below breakdown
• B. unbiased with no thermal carriers
• C. forward biased beyond its knee region
• D. connected with both terminals at the same potential only

Question 2 · difficulty L1 · understanding

In forward bias, a p-n diode is connected with p-side to

• A. the negative terminal
• B. ground only with no second connection
• C. another reverse-biased p-side
• D. the positive terminal of the supply

Question 3 · difficulty L2 · understanding

In reverse bias, the diode current before breakdown is typically

• A. small and nearly saturated
• B. larger than forward current by orders of magnitude
• C. exactly proportional to voltage like an ideal resistor
• D. zero because no minority carriers exist

Question 4 · difficulty L2 · application

The knee or cut-in voltage on a forward I-V curve marks

• A. the reverse-breakdown voltage
• B. the region where forward current begins increasing rapidly
• C. zero current at every voltage
• D. the maximum possible resistance

Question 5 · difficulty L3 · application

A silicon diode has a forward drop approximated as 0.7 V in a simple circuit. With a 5 V source and 430 Ω series resistor, current is about

• A. 1 mA
• B. 100 mA
• C. 10 mA
• D. 0.7 mA

Question 6 · difficulty L3 · application

A diode is reverse biased well below breakdown. Increasing reverse voltage modestly changes current

• A. by the same linear Ohmic amount as a resistor
• B. from positive to infinite instantly
• C. to a large majority-carrier current
• D. very little compared with forward-bias changes

Question 7 · difficulty L4 · analysis

The dynamic resistance of a forward-biased diode at an operating point is approximated by

• A. ΔV/ΔI
• B. V/I only in every nonlinear case
• C. ΔI/ΔV
• D. VI

Question 8 · difficulty L4 · analysis

A diode's reverse current rises suddenly at a particular voltage. This region is called

• A. forward knee
• B. breakdown
• C. open circuit
• D. zero-bias equilibrium

Question 9 · difficulty L5 · analysis

Why is a diode considered a nonlinear device?

• A. It cannot carry current
• B. Its resistance is exactly constant
• C. Its current is not proportional to applied voltage over its operating range
• D. Its I-V graph is always a straight line through the origin

Question 10 · difficulty L5 · analysis

Two identical diodes are tested at the same temperature. One shows large current for +0.8 V and tiny current for -0.8 V. This asymmetry demonstrates

• A. Ohmic symmetry
• B. zero junction barrier
• C. equal majority populations on both sides
• D. rectifying behaviour