Gcse Electronics Aqa - Revision Flashcards

Front 1

Resistor

Back 1

Limits current

Front 2

Variable resistor

Back 2

Limits current and the value of the resistance can be changed

Front 3

LDR - Light Dependent Resistor

Back 3

Input transducer - Increasing light decreases resistance.

Front 4

Thermistor

Back 4

Input transducer - Increasing temperature decreases resistance of component.

Front 5

Lamp

Back 5

Output transducer - converts electrical signal to light. May need a driver (transistor)

Front 6

Fuse

Back 6

Safety device - melts and breaks circuit if excess current is present.

Front 7

Ammeter

Back 7

Measures current (I) in a circuit.

Front 8

Voltmeter

Back 8

Measures voltage (V) across components.

Front 9

Cell

Back 9

provides a DC voltage

Front 10

capacitor

Back 10

Stores charge. Often used to smooth signals or in timing circuits.

Front 11

electrolytic capacitor

Back 11

Stores charge. It is polarised (has a + and - terminal). Often used to smooth signals or in timing circuits.

Front 12

diode

Back 12

Only allows current flow in one direction. Used in rectification (making AC into DC). Typically has a 0.7 V drop across it. Is polarised (has a + and a - side)

Front 13

LED (light emitting diode)

Back 13

Only allows current to flow in one direction, a light goes on when current flows. Often used as output signal. Typically has a 2.0 V drop across it.
Must be protected with a resistor. Is polarised (has a + and a - side)

Front 14

NPN Bipolar Transistor

Back 14

Used as an electronic switch. 3 terminals: Collector, Base, Emitter.
Small current at BASE releases a large current between Collector and emitter. Base needs a protective resistor.

Front 15

MOSFET Transistor

Back 15

Used as an electronic switch.
3 terminals: Drain, Gate, Source. Small voltage at GATE allows a large current between Drain and Source. Needs a protective diode for semiconductor.

Front 16

AND Gate

Back 16

Logic gate - gives high output (Q) only when 2 inputs (A and B) are high .

Front 17

OR Gate

Back 17

Logic gate - gives high output (Q) if either or both inputs (A or B) are high.

Front 18

NOT Gate

Back 18

Logic gate - inverts A.

Front 19

NAND Gate

Back 19

Logic gate - gives high output (Q) opposite of AND gate.

Front 20

NOR Gate

Back 20

Logic Gate - Gives high output (Q) opposite to OR gate. (High only when both A and B are low)

Front 21

D-type flip flop

Back 21

Simple memory / Latch.
Data (1 or 0) is stored in D. When clock goes high, Q copies D. Q remains in that state until next rising edge of CLK.

Front 22

Op - Amp / Comparator

Back 22

Compares non-inverting voltage (+) to inverting voltage (-).
If V+ is bigger, output is Vs.
If V- is bigger, output is 0V or -Vs

Can be considered a 1-bit Analog to Digital Converter (ADC)

Front 23

Transformer

Back 23

Converts one voltage to another, usually transforming high mains voltage (240V) to a safer, lower voltage (15V)

Front 24

Half Wave Rectification

Back 24

Making AC current into DC current using just 1 diode and a capacitor (for smoothing)

Front 25

Bridge (Full Wave) rectification

Back 25

Making AC current into DC current using a set of 4 diodes and a capacitor (for smoothing)

Front 26

What are the colours and names of pins for a 3-pin mains plug?

Back 26

Earth - brown
Live - green and yellow
Neutral - Blue

Front 27

Input Transducer

Back 27

Converts sound/light/heat/mechanical energy to electrical energy/signal.

ex. microphone, LDR, thermistor,button

Front 28

Output Transducer

Back 28

Converts electrical signal into sound/light/heat/motion.

ex. speaker, lamp/LED, heater, motor

Front 29

List 4 effects of electric shock

Back 29

Burns
Shock to nervous system
Stop the heart
Body thrown back

Front 30

Describe 3 steps to take in an emergency

Back 30

1. Turn of mains.
2. Get help
3. Use first aid.

Front 31

What are some protective measures to take when working with electricity?

Back 31

Don't have liquid near appliances
Wear rubber soled shoes
Don't have wet hands
Never work alone

Front 32

Why is a disconnected capacitor a possible danger?

Back 32

It can still have a large charge and produce a shock.

Front 33

How does a thermal circuit breaker work?

Back 33

Breaks the circuit if there is too much current, but can be reset.

Front 34

Analogue Devices

Back 34

Take inputs/outputs with a range of values. Examples: amplifiers, sensors,

Front 35

Digital Devices

Back 35

Take inputs/outputs only with a "high" or "low" value, often written as 1 or 0.

Front 36

Monostable

Back 36

Circuit with a 555 chip to make a time delay.

Front 37

Astable

Back 37

Circuit using a 555 chip to make a clock or pulse.

Front 38

Resistance Calculation

Back 38

R = V / I

V = voltage across a device (Volts)
I = current through a device (Amps)

Front 39

Aerial

Back 39

concerts radio waves into electrical signal

Front 40

RF tuned circuit

Back 40

selects frequency of required station

Front 41

demodulator

Back 41

separates the radio carrier signal from the audio signal (may use a diode to do this).

Front 42

af amplifier

Back 42

amplifies (increases) the audio signal

Front 43

loudspeaker

Back 43

converts electrical energy/signal to sound.

Front 44

AM

Back 44

Amplitude Modulation

Front 45

FM

Back 45

Frequency Modulation

Front 46

Sensitivity

Back 46

Ability to pick up a weak signal

Front 47

Selectivity

Back 47

Ability to distinguish between frequencies.

Front 48

Frequency Divider

Back 48

Can be created from D-type flip-flops by connecting NOT-Q to data, and connecting the Q of one D-type to the CLOCK of the next.