Solid-State Devices Flashcards

Questions and Answers

What is a solid-state device?

An electronic device in which electricity flows through solid semiconductor crystals rather than through vacuum tubes.

What types of semiconductors are there?

Diode

Transistor

Thyristor

All of the above (correct)

What is a semiconductor?

A substance that can only conduct electricity in certain environments such as when heated, light is applied, or in the presence of an electric field.

What types of semiconductor materials are there?

Both A and B Signup and view all the answers

What is voltage rectification?

The process of converting AC to DC using diodes. Signup and view all the answers

What is an intrinsic semiconductor?

Silicon atoms arranged in a crystalline solid structure without free electrons due to the absence of impurities. Signup and view all the answers

How is the n-pole created?

By adding an impurity such as arsenic, antimony, or phosphorus to an intrinsic semiconductor. Signup and view all the answers

How is the p-pole created?

By adding impurities such as aluminium, boron, or indium to an intrinsic semiconductor. Signup and view all the answers

What is the difference between n-type and p-type semiconductors?

N-type semiconductors have an abundance of negatively charged carriers (electrons), while p-type semiconductors have positive carriers known as holes. Signup and view all the answers

How do holes move?

Holes attract neighboring electrons, and when filled by an electron, leave another hole, creating an appearance of positive charge movement. Signup and view all the answers

What is a diode?

A device made from a single piece of semiconductor material with a positive 'P region' and a negative 'N region'. Signup and view all the answers

What are majority carriers?

Electrons in N-type semiconductors and holes in P-type semiconductors. Signup and view all the answers

What is a minority carrier?

A free electron in the P-type or a hole in the N-type semiconductor that is close to the junction. Signup and view all the answers

How do you increase the flow of minority carriers?

By increasing the temperature, which thermally produces more minority carriers. Signup and view all the answers

How is a forward biased P-N junction formed?

When the p-type region is connected to the positive terminal and the n-type region is connected to the negative terminal of a voltage source. Signup and view all the answers

What happens in a forward biased P-N junction?

Electrons and holes cross the junction, forming an electric current. Signup and view all the answers

How is a reverse biased P-N junction formed?

When the positive terminal of a voltage source is connected to the n-type region and the negative terminal is connected to the p-type region. Signup and view all the answers

What is breakdown voltage?

The reverse voltage at which the diode fails to act as a rectifier. Signup and view all the answers

What is a thyristor?

A silicon controlled rectifier (SCR) that acts as an electronic switch. Signup and view all the answers

What is a triac?

A device that can switch on in both negative and positive potential differences. Signup and view all the answers

When are solid-state diodes used?

For the rectification of AC supply to devices requiring DC supply. Signup and view all the answers

When are transistors used?

In electronic timing circuits and safety interlocks. Signup and view all the answers

When are thyristors/triacs used?

For primary switching of x-ray exposure. Signup and view all the answers

Microprocessors have __________.

many applications Signup and view all the answers

Study Notes

Solid-State Devices Overview

Solid-state devices utilize solid semiconductor crystals for electric current flow, contrasting with vacuum tubes.
Semiconductor types include diodes, transistors, and thyristors.

Semiconductors

Semiconductors conduct electricity under specific conditions (temperature, light, electric field) due to their small energy gap.
Two primary semiconductor materials exist: n-type (negatively charged) and p-type (positively charged).

Voltage Rectification

Rectification converts AC power into DC, essential for devices like x-ray tubes. Silicon diodes are used for this conversion.

Intrinsic and Extrinsic Semiconductors

Intrinsic semiconductors (pure silicon) lack free electrons, while extrinsic semiconductors gain conductivity through added impurities.
N-pole is formed by adding elements like arsenic or phosphorus; p-pole is created with elements like aluminum or boron.

P-N Junction

A p-n junction forms by joining n-type and p-type materials, resulting in the attraction of holes and electrons, creating a depletion region.
This junction acts as a potential barrier preventing flow of majority carriers while allowing minority carriers to cross.

Biasing P-N Junctions

Forward bias occurs when p-type is connected to positive voltage, allowing current flow.
Reverse bias applies positive voltage to n-type, preventing current flow except for very low reverse current.

Transistors

Transistors consist of alternating n-type and p-type layers (NPN or PNP) and are categorized by their biasing behavior.
In NPN transistors, base-emitter junction forms forward bias, creating current flow, while base-collector junction remains reverse biased until stimulated.

Field-Effect Transistors (FETs)

FETs control current flow through a semiconductor using an electric field, structured with a conducting channel and a gate.
Variants include junction field-effect transistor (JFET) and metal oxide semiconductor field effect transistor (MOSFET).

Thyristors and Triacs

Thyristors are silicon-controlled rectifiers with four layers that act as electronic switches; they can trigger conduction under a specific gate signal.
Triacs, capable of switching with either polarity, allow for bidirectional current flow in AC applications.

Applications of Solid-State Devices

Solid-state diodes are primarily used for rectifying AC to DC supplies.
Transistors serve in electronic timing circuits and safety interlocks.
Thyristors and triacs are employed in the primary switching of x-ray exposures, controlling high-power applications.
Logic circuits monitor function sequences before operations like x-ray exposure.
Microprocessors find diverse applications across various electronic systems.

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Test your knowledge of solid-state devices with these flashcards. This set covers essential terms and definitions related to semiconductors, including types and functionalities. Perfect for students and professionals looking to refresh their memory on this critical topic.