exam questions

Question 1

If an LED has a 2v drop in a 4.5v circuit. How much voltage?

Answer 1

2.5v

Question 2

why are IC sockets useful

Answer 2

1. stops component from being damaged by soldering.
2. the IC is easily removable to swap or change if in the wrong orientation.
3. easier to replace a faulty chip

Question 3

what is bistable

Answer 3

a latching device with 2 stable states (high or low, on or off)

Question 4

in a decade counter where is the enable pin connected

Answer 4

connected low

Question 5

Uses of CAD

Answer 5

1. testing the idea to see if the components are connected correctly and have the right values.
2. Designing the circuit in circuit wizard.
3. Lets a person visualise their design and or circuit idea that can be sent direct to a printer, cnc or cad.

Question 6

what does a potentiometer do?

Answer 6

adjust voltage and resistance to set light/heat level for sensors.

Question 7

3 legs of an FET

Answer 7

gate, drain, source

Question 8

3 legs of a transistor

Answer 8

base, collector, emmiter

Question 9

3 legs of a thyristor

Answer 9

gate, anode, cathode

Question 10

advantages of rapid prototyping

Answer 10

1. complex 3 d shapes made, they can be amended if needed.
2. made from a 3d drawing
3. complex components are produced quickly.

Question 11

How does vacuum forming work

Answer 11

Material clamped into place
Heat applied
Former raised into material
Vacuum pump switched on
Pump off / table lowered
Formed shape removed

Question 12

voltage for a microconrtoller

Answer 12

5v

Question 13

voltage regulator purpose

Answer 13

to stabilise the voltage for a circuit so it doesn’t damage any components

Question 14

purpose of a darlington pair

Answer 14

to go from a low current device to a high current output like a speaker from a microcontroller.

Question 15

uses for standards in manufacture

Answer 15

1. upholds reputation so sell more.

2. to make sure there is no fault which will need to be compensated.

Question 16

advantages of pick and place component machines

Answer 16

much faster than humans

need for less employees so save money

Question 17

what a thyristor

Answer 17

a latching component which stays on even once currents stop being applied.

Question 18

why is a diode used?

Answer 18

protect from back emf

protect components

Question 19

what is a pull down resistor

Answer 19

connects input low, so prevents accidental triggering

Question 20

what is switch bounce?

Answer 20

Several pulses produced from each press of the switch

Question 21

how to stop switch bounce

Answer 21

using a debouncer circuit/ monostable to create a clean signal

Question 22

advantages of injection moulding for high production

Answer 22

low skilled workers needed
mould can be re used
low cost for each component

Question 23

3 things that improve a vacuum forming mould

Answer 23

rounded corners, vent holes and filleted joints

Question 24

monostable works by

Answer 24

pin 2 connecting low, circuit triggered.
pin 3 high then low until pin 6 is measuring how full capcitor
pin 7 discharges
output turn on for this time delay

Question 25

astable

Answer 25

same as mono but pin 2 is triggered by discharge of pin 6

Question 26

capacitor polarised sides are shown by

Answer 26

long and short lead | minus sign

Question 27

how can voltage drop be measured

Answer 27

by a multi meter

Question 28

how to use a multi meter

Answer 28

select v range attach a lead to anode and cathode connect probes either side of the componet take a reading

Question 29

prototypes are

Answer 29

working models made in development stages

Question 30

resistors

Answer 30

used for pulling high and low and to protect componets from too much current

Question 31

benifits of packaging a darlington pair in 1 component

Answer 31

fewer components so reliable | smaller circuit board

Question 32

function of an astable

Answer 32

to create a flashing output bby being a pulse generator

Question 33

digital signal

Answer 33

2 states on or off

Question 34

anologue signal

Answer 34

varying signal

Question 35

advantages of a microcontroller

Answer 35

wide range of features programmable adaptive inputs and outputs

Question 36

one off product

Answer 36

specialised, complex made for 1 client only 1 made expensive to produce

Question 37

high volume production

Answer 37

tooling required to be set up once. skilled workforce isnt needed made in big quantities

Question 38

advantages to seven segment display to an led

Answer 38

looks better easier solder cos less legs Single component so not many components

Question 39

what is a one of product

Answer 39

a singular product complex ans specialised. requires a skilled workforce and time and money

Question 40

high volume productions

Answer 40

many products are made. low skilled workforce

Question 41

what is a prototype

Answer 41

working model consisting of the correct measurements used as a real world testing