GCSE Electronics Eduqas

This subject is broken down into 37 topics in 6 modules:

  1. Component Knowledge 5 topics
  2. Circuit Analysis and Design 10 topics
  3. Digital Electronics 6 topics
  4. Microcontrollers and Programming 5 topics
  5. Power Supplies 6 topics
  6. Communication Systems 5 topics
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  • 6
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  • 37
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  • 13,609
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  • 1+
    hours of audio lessons

This page was last modified on 28 September 2024.

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Electronics

Component Knowledge

Passive Components: Resistors, Variable Resistors, Capacitors, Inductors

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Passive Components: Resistors, Variable Resistors, Capacitors, Inductors

Resistors

  • Resistors are electrical devices that limit or regulate the flow of electrical current in an electronic circuit.
  • They are characterised by their resistance value (measured in Ohms, Ω) which, in simplified terms, describes their ability to resist the flow of electricity.
  • They follow Ohm's Law (V=IR), which states that the voltage (V) through a resistor is equal to the product of the current (I) through it and its resistance (R).
  • Resistors are linear devices meaning that their voltage is directly proportional to the current.
  • Fixed resistors have a defined value that cannot change. Examples include carbon film resistors or metal oxide resistors.
  • Resistors can come in different power ratings, indicating how much power they can safely dissipate as heat.

Variable Resistors

  • A variable resistor, also called a potentiometer, allows the resistance to be changed within a certain range.
  • Variable resistors can be used to adjust current, divide voltage, or simply as a tuning component in some circuits.
  • It comprises of a resistor with a sliding contact (wiper) which makes it possible to adjust the resistance.

Capacitors

  • Capacitors store electrical energy in an electric field.
  • They consist of two conductive plates separated by an insulator, known as the dielectric.
  • The capacitance, measured in Farads (F), is the measure of a capacitor's ability to store electrical energy.
  • When voltage is applied to a capacitor, an electric field is created between the plates, causing a positive charge to accumulate on one plate and a negative charge on the other.
  • Capacitors block direct current (DC) and allow alternating current (AC) to pass through.

Inductors

  • Inductors, also known as coils, are passive devices used in electronic circuits to store energy in a magnetic field when electric current is flowing through it.
  • The unit of inductance is the Henry (H).
  • They are often used in filters, sensors and transformers.
  • They are characterised by their ability to resist changes in current and can block or slow down changes in voltage.
  • Similar to capacitors, inductors also affect AC and DC differently. They pass direct current (DC) and can resist or block alternating current (AC) due to electromagnetic induction.

Course material for Electronics, module Component Knowledge, topic Passive Components: Resistors, Variable Resistors, Capacitors, Inductors

Electronics

Digital Electronics

Encoders, Decoders, and Multiplexers

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Encoders, Decoders, and Multiplexers

Encoders

  • Encoders are digital combinational circuits used for the conversion of analog signals into binary codes.
  • Main aim is to minimise the number of data lines and to simplify the structure.
  • A very common type of encoder is known as priority encoder, which not only produces digital code corresponding to the active input but also produces another digital code known as priority bit.

Types of Encoders

  • Binary Encoders have numerous inputs and outputs. The outputs are a binary code representing the digital version of the analog input.
  • Priority Encoders differ slightly where when multiple inputs are active, the encoder prioritises the highest-numbered input.
  • A specific type of encoder called a line encoder, processes incoming digital data into a form that can be used by other parts of the digital system.

Decoders

  • Decoders are the opposite of encoders. They take binary output codes and convert them back into a form that can be understood by other types of circuits.
  • They contain binary input lines and multiple output lines. Depending on the combination of binary input, they produce a high output on the specified line.
  • They are often used in memory chips, data multiplexing, 7-segment displays.

Types of Decoders

  • Binary Decoders, also known as n-to-2n decoder, have 'n' inputs and maximum '2n' outputs.
  • BCD to 7-Segment Decoders are specifically used in output devices such as LED and LCD numerical displays.

Multiplexers

  • Multiplexer, or MUX, is a combinational circuit responsible for selecting binary information from one of the many input lines and routing it directly to a single output line.
  • Selection of the particular input line is controlled by a set of selection lines.
  • Depending on the number of input lines, these are named as 2:1, 4:1, 8:1, 16:1 multiplexers.

Types of Multiplexers

  • 2:1 Multiplexer has 2 input lines, 1 output line, and 1 selection line.
  • 4:1 Multiplexer has 4 input lines, 1 output line, and 2 selection lines.
  • 8:1 Multiplexer has 8 input lines, a single output line, and 3 selection lines.

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Understanding Encoders, Decoders and Multiplexers is crucial for a clear comprehension of how digital electronics operate. It's all about conversion and routing of information in a system - a critical knowledge for the digital world.

Course material for Electronics, module Digital Electronics, topic Encoders, Decoders, and Multiplexers

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