Chapter 1 Flashcards

Electronic Components and Fundamental Circuits Principles

1
Q

What are resistors?

A

Electronic components that resist or control the flow of electric currents in electrical appliances and devices.

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2
Q

Types of Resistors

A
  • Fixed
  • Variable
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3
Q

What is a potentiometer?

A

A type of small variable resistor which can have its resistance value changed with a screwdriver

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4
Q

What are resistors used for?

A

To prevent damage to devices/systems or to ensure they operate within safe limits.

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5
Q

What are resistors normally composed of?

A

Metal and Carbon

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6
Q

What happens to heat when a current flows through a resistor?

A

It dissipates

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7
Q

What are capacitors?

A

Electronic components that store and release electrical energy in a electric field, which preserves voltage

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8
Q

What are capacitors used for?

A

They are used in power supplies to provide a temporary backup of electrical energy and in many devices to stabilise voltage levels.

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9
Q

What are inductors?

A

Electronic components that temporarily store energy in a magnetic field.

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10
Q

What does a inductor consist of?

A

A conducting material such as copper wrapped around a core made from a magnetic material.

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11
Q

What is the purpose of inductors?

A

Inductors store energy in a magnetic field when current flows through their coils. They resist changes in the flow of electric current.

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12
Q

Capacitors vs Inductor

A

Inductors store energy in a magnetic field
Capacitors store energy in a electrical field

Inductors conserve current
Capacitors conserve voltage

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13
Q

What is a diode?

A

Devices that allow electrical current to flow in one direction while blocking it in the other direction.

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14
Q

Where are diodes used?

A
  • Power supplies
  • DC-to-DC converters
  • Power inverters
  • Switches in digital logic circuits
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15
Q

What are LEDs?

A

Tiny electric bulbs that use small amounts of
electricity, they emit light when electrical current passes through them.

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16
Q

What does LEDs stand for?

A

Light Emitting Diodes

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17
Q

What are Op-amps?

A

Electronic devices that amplify the difference in voltage between the two inputs (inverting and non-inverting). They make small changes in voltage much larger.

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18
Q

What does Op-amps mean?

A

Operational Amplifier

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19
Q

Where are Op-amps used?

A

In signal amplification

20
Q

What are switches?

A

Devices that open or close an electrical circuit. When you flip a switch, it either allows electricity to flow through (closed) or blocks it (open).

21
Q

What is Ohm’s law?

A

Voltage is directly proportional to the current provided R remains constant.

The current is inversely proportional to the resistance provided the voltage remains constant.

22
Q

Mathematical expression of Ohm’s law

A

Voltage = Current * Resistance or V = I R

23
Q

What is the relationship between current and resistance?

A

Current is inversely proportional to resistance

24
Q

Symbol and Unit of Voltage

A

V and Volt

25
Q

Symbol and Unit of Current

A

I and A (Ampere)

26
Q

Symbol and Unit of Resistance

A

R and Ω (Ohm)

27
Q

What is voltage?

A

Electrical pressure that causes charged electrons to flow through a conducting
loop, enabling them to do work such as illuminating a light bulb.

28
Q

What are the types of voltage?

A
  • direct (DC)
  • alternating (AC)
29
Q

What type of polarity does AC and DC have?

A

DC maintains the same polarity whilst with AC the polarity changes direction periodically.

30
Q

What is polarity?

A

The direction of the current

31
Q

What is a DC power supply?

A

An electrical device that is capable of generating a constant voltage that a direct voltage needs.

32
Q

What is the current?

A

The rate of charged particles (electrons) through an electric circuit

33
Q

How does the electric current flow in a circuit?

A

The conventional flow of an electric current is from the positive terminal towards the negative terminal of a battery or power supply.

34
Q

How to work out the resistance in a parallel circuit?

A

1/Rₜ = 1/R₁ + 1/R₂ + 1/R₃
or
V/Rₜ = V/R₁ + V/R₂ + V/R₃

35
Q

What is the voltage divider rule?

A

A way to determine voltage values across resistors when placed in series

36
Q

Equation for the voltage divider rule

A

V₁ = R₁ / (R₁ +R₂) x Vₜ
V₂ = R₂ / (R₁ + R₂) x Vₜ

37
Q

What is the current divider rule?

A

A method to determine current values through resistors when they are placed in parallel.

38
Q

Equation for the current divider rule

A

I₁ = (R₂ / (R₁ + R₂)) x Iₜ
I₂ = (R₁ / (R₁ + R₂)) x Iₜ

39
Q

When is the current divider rule not used directly?

A

If the circuit contains more than two resistors in parallel

40
Q

What is Kirchhoff’s Current Law?

A

The sum of the currents flowing through all the wires that meet at a node or point in a circuit is equal to zero.

Flowing ways is negative
Flowing towards is positive

Example. I₁ - I₂ + I₃ + I₄ = 0

41
Q

For Kirchhoff’s current law describe how the currents flowing from and away from the node are presented?

A

The current flowing towards the node is taken to be positive and that flowing away from the node to be negative.

42
Q

What is Kirchhoff’s Voltage Law?

A

The sum of the voltages within any loop in a circuit is equal to the sum of the products of the currents and resistors in the various parts of the loop.

43
Q

Equation of Kirchhoff’s Voltage Law

A

V₁ - I₁ R₁ - (I₁ - I₂) x R₂ = 0
(I₁ - I₂)R₂ - V₂ - I₂R₃ - I₂R₄ - I₂R₅ = 0

44
Q

Define Electrical Power and an example

A

The rate of change of energy
i.e. the change of electrical energy with time.

45
Q

Symbol and Unit of Electrical Power

A

P and Watt (W)

46
Q

Equation for Electrical Power

A

P = VI
P= I²R
P = V² / R