Semiconductors and Diode Theory

Materials that doesn't allow flow of electrons

• Conductor

• Insulator

• Semiconductor

• Semi-insulator

Answer explanation

Insulators are materials that do not allow the flow of electrons, making them poor conductors of electricity. In contrast, conductors allow electron flow, while semiconductors have intermediate properties.

Gap in energy between the bound state and the free state, between the valence band and conduction band.

• Energy Gap

• Conduction Gap

• Valence Gap

• Electron Gap

Answer explanation

The term 'Energy Gap' refers to the difference in energy between the valence band and conduction band in a material. This gap is crucial for understanding electrical conductivity and semiconductor behavior.

In forward bias, the diode's anode is connected to the:

• Negative terminal

• Ground

• Positive terminal

• Open terminal

Answer explanation

In forward bias, the diode allows current to flow when the anode is connected to the positive terminal and the cathode to the negative terminal. This configuration enables the diode to conduct electricity.

Which diode emits light?

• Zener Diode

• LED

• Tunnel Diode

• Schottky Diode

Answer explanation

The LED (Light Emitting Diode) is specifically designed to emit light when an electric current passes through it, making it the correct choice. Other diodes like Zener, Tunnel, and Schottky do not emit light.

What component converts AC to DC?

• Resistor

• Capacitor

• Diode

• Transformer

Answer explanation

A diode is a semiconductor device that allows current to flow in one direction only, effectively converting alternating current (AC) to direct current (DC). This makes it the correct choice for the conversion process.

A transformer works on the principle of:

• Ohm's Law

• Magnetic Resonance

• Electromagnetic Induction

• Electric Field

Answer explanation

A transformer operates on the principle of electromagnetic induction, which involves the generation of voltage across a coil when it is exposed to a changing magnetic field. This is the fundamental principle behind its operation.

What kind of signal is output from a full-wave rectifier?

• Pure AC

• Constant DC

• Pulsating DC

• Zero Voltage

Answer explanation

A full-wave rectifier converts both halves of an AC signal into a pulsating DC signal. This output is not constant, as it varies in amplitude, hence the correct answer is pulsating DC.

The main purpose of a filter in power supplies is to:

• Block Current

• Increase Voltage

• Reduce Ripple

• Control Temperature

Answer explanation

The main purpose of a filter in power supplies is to reduce ripple, which refers to the fluctuations in voltage. By smoothing out these fluctuations, filters ensure a more stable and reliable power output.

Which diode is used for voltage regulation?

• Zener Diode

• LED

• Tunnel Diode

• Varactor Diode

Answer explanation

The Zener diode is specifically designed to operate in reverse breakdown, allowing it to maintain a constant voltage across its terminals, making it ideal for voltage regulation. Other diodes do not serve this purpose.

What does a capacitor store?

• Current

• Magnetic Field

• Voltage

• Resistance

Answer explanation

A capacitor stores voltage by accumulating electric charge on its plates. It does not store current, magnetic fields, or resistance, making 'Voltage' the correct answer.