Diodes topics include: The basics of diode, types of diodes which includes zener diode and others, limiting and clamping circuits, rectifiers and characteristics of junction diode and diode forward characteristics modelling. A diode is an electronic component that allows electricity to flow in one direction. Diodes are also known as "rectifiers".  Diodes are made of two electrodes, called the anode and the cathode, and are usually made from semiconductor materials like silicon, germanium, or selenium. Some diodes have metal electrodes in a chamber filled with a pure elemental gas at low... Show more

Diodes topics include: The basics of diode, types of diodes which includes zener diode and others, limiting and clamping circuits, rectifiers and characteristics of junction diode and diode forward characteristics modelling.

A diode is an electronic component that allows electricity to flow in one direction. Diodes are also known as "rectifiers". 

Diodes are made of two electrodes, called the anode and the cathode, and are usually made from semiconductor materials like silicon, germanium, or selenium. Some diodes have metal electrodes in a chamber filled with a pure elemental gas at low pressure. 

Diodes can:
Regulate the flow of electricity
Maintain a constant voltage
Extract signals from radio waves
Protect circuits by limiting the voltage
Transform AC into DC 

Diodes are classified according to their characteristics and come in many different types, including rectifiers, switching diodes, and Schottky. 

When selecting a diode, you can consider things like:
Forward conduction pressure drop
Rated current
Maximum average rectified current
Maximum surge current
Maximum reverse peak voltage
Maximum reverse voltage
Maximum operating frequency
Reverse recovery time

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Electronic Devices and Circuits Practice Test: Diodes

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25 Questions

1. The value of I and V for the circuit shown below are

2A and 0V respectively-2A and -5V respectively2A and 5V respectively-2A and 5V respectively

2. Zener diodes can be effectively used in voltage regulator. However, they are these days being replaced by more efficient

MOSFETOperational AmplifierIntegrated CircuitsNone of these

3. The other name for bias point is

Terminal pointNode pointStatic pointQuiescent point

4. In many applications, a conducting diode is modeled as having a constant voltage drop, usually approximately

1 V0.7 V0.1 V7V

5. A diode

All of the mentionedIs the simplest of the semiconductor devicesHas a characteristic that closely follows that of a switchIs two terminal device

6. Calculate the change in the voltage when R_L is connected as shown below.

-25 mA-20 mA-15 mA-10 mA

7. Which of the following is true for a bridge rectifier?

A transistor of higher number of coil is required for center tapped rectifier than the identical bridge rectifierAll of the mentionedThe peak inverse voltage or PIV for the bridge rectifier is lower when compared to an identical center tapped rectifierThe output voltage for the center tapped rectifier is lower than the identical bridge rectifier

8. A designer requires a shunt regulator of approximately 20 V. Two kinds of Zener diodes are available: 6.8-V devices with r_z of 10 Ω and 5.1-V devices with r_z of 30 Ω. For the two major choices possible, find the load regulation. In this calculation neglect the effect of the regulator resistance R.

30mV/mA and 60mV/mA respectively-30mV/mA and -120mV/mA respectively-30mV/mA and 120mV/mA respectively-60mV/mA and +60mV/mA respectively

9. The graphical method of modeling a diode characteristics is based on

Exponential methodSmall signal approximationIteration methodConstant voltage drop method

10. The units frequently used to measure the forward bias and reverse bias current of a diode are

µA and µA respectivelymA and µA respectivelymA and mA respectivelyµA and mA respectively

11. Diodes can be used in the making of

All of the mentionedRectifiersLED lampsLogic gates

12. The V₀ vs V_I curve for the below circuit is

13. Limiting and clamping circuits are employed in

All of the mentionedFM transmittersProduction of various signal waveforms such as trapezoidal, square or rectangular wavesTelevision receivers and transmitter

14. Partial specifications of a Zener diode is provided. V_Z = 10.0 V, V_ZK = 9.6 V, and I_ZT = 50 mA. Assuming that the power rating of a breakdown diode is established at about twice the specified Zener current (I_ZT), what is the power rating of each of the diodes described above?

1.04 mW0.104 W1.04 W10.4 mW

15. A 9.1-V zener diode exhibits its nominal voltage at a test current of 28 mA. At this current the incremental resistance is specified as 5 Ω. Find VZ0 of the Zener model.

9.24V9.03V8.96V9.17V

16. The figure below shows a circuit for an AC voltmeter. It utilizes a moving-coil meter that gives a full-scale reading when the average current flowing through it is 1 mA. The moving-coil meter has a 50-Ω resistance. The value of R that results in the meter indicating a full-scale reading when the input sine-wave voltage V_I is 20 V peak-to-peak is

3.133 kΩ56.183 Ω3.183 Ω3.183 kΩ

17. Which of the following is not true for a Schottky-Barrier Diode (SBD)?

It is formed by bringing metal into contact with a moderately doped n-type semiconductor material.The forward voltage drop of a conducting SBD is lower than that of a pn-junction diode.In the SBD, current is conducted by mainly by minority carriers.SBD are used in the design of a special form of bipolar-transistor logic circuits

18. Which of the following is not true for the duty cycle of a waveform?

60% duty cycle means that the waveform is active for 40% of the total timeDuty cycles can be used to describe the percent time of an active signal in an electrical deviceDuty cycle can be used to determine the percentage of the time a signal is active50% duty cycle means that the waveform is non-active for 50% of the total time

19. The maximum load current that can be drawn is

1.4 mA2.3 mA2.5 mA1.8 mA

20. The Q-point of the zener diode in the circuit shown below is

(0.34 mA, 4 V)(0.94 mA, 4 V)(0.94 mA, 4.93 V)(0.34 mA, 4.93 V)

21. For a half-wave rectifier having diode voltage V_D and supply input of V_I, the diode conducts for π – 2Θ, where Θ is given by

tan-1 VD/VI – VIsin-1 VD/VItan -1 VD/VIsin-1 VD/VI – VI

22. Consider an AC sine wave voltage signal being used to connect a diode and a resistor as shown in the figure. The variation of the voltage across the diode (V_d) with respect to time (t) is given by

None of these

23. Bridge rectifier is an alternative for

Full wave rectifierNone of theseHalf wave rectifierPeak rectifier

24. Zener diodes are also known as

Forward bias diodeNone of theseBreakdown diodeVoltage regulators

25. Optoisolator is

A combination of LED and varactor in the same packageA combination of photodiode and Schottky-Barrier Diode in the same packageA combination of a varactor and photodiode in the same packageA combination of LED and a photodiode in the same package