Kitronik QUIZ BUZZER KIT User manual

QUIZ BUZZER
KIT
WHO ANSWERED FIRST? FIND OUT WITH THIS

BUILD INSTRUCTIONS
Before you put any components in the board or pick up the soldering iron,
just take a look at the Printed Circuit Board (PCB). The components go in the
side with the writing on and the solder goes on the side with the tracks and
silver pads.
PLACE RESISTORS
Start with the seven resistors. The text on the PCB
shows where R1, R2, etc go. Make sure that you put
the resistors in the right place.
1
PCB Ref
R1, R2, R3, R5 & R7
R4 & R6
Value
10K
220Ω
Colour Bands
Brown, black, orange
Red, red, brown
SOLDER THE IC HOLDERS
Solder the two Integrated Circuit (IC) holders into
U1 and U2. When putting them into the board, be
sure to get them the right way around. The notch on
the IC holders should line up with the notch on the
lines marked on the PCB.
2
SOLDER THE TRANSISTOR
Solder the transistor into the board where it is labeled
Q1. The transistor is a BC547B and will be marked
C547B on the body of the device. Make sure the device
is the correct way around. The shape of the device
should match the outline on the PCB.
3

SOLDER THE THYRISTORS
Solder the two thyristors into the board where it is
labeled Q2 and Q3. These are marked with the part
number 2N5061. Again make sure the device is the
correct way around. The shape of the device should
match the outline on the PCB.
4
SOLDER THE BUZZER
The buzzer should be soldered into the ‘buzzer’
terminal. The red wire must go to the ‘+’ terminal
and the black wire must go to the ‘-’ terminal.
6
ATTACH THE BATTERY CLIP
Now you must attach the battery clip. Start by feeding
the leads through the strain relief hole near U2. The
wire should be fed in from the rear of the board.
7
SOLDER THE LEDs
Solder the two Light Emitting Diodes into LED1 and
LED2. The red LED should go in LED1 and the green
LED in LED2. The LEDs won’t work if they don’t go in
the right way around. If you look carefully one side of the
LED has a flat edge, which must line up with the flat edge
on the lines on the PCB. You may want to solder them in at a
specific height depending upon how you have designed your enclosure (if
you are making one). Once you are happy solder them into place.
5

ATTACH THE SWITCHES
Attach the two push to make switches these have a
red button. First cut and strip four short lengths of the
wire supplied. Solder one to each of the two terminals
on the switches. Then solder the other end of the wires
on one of the switches to the PCB where it is marked
‘SW1’. It does not matter which way around the two wires go.
Then do the same with the wires on the other switch but this time connect
them to the PCB where it is marked ‘SW2’.
8
ATTACH THE RESET SWITCH
Attach the reset switch, this has a black button. First
cut and strip two short lengths of the wire supplied.
Solder one to each of the two terminals on the switch.
Then solder the other end to the PCB where it is
marked ‘reset’. It does not matter which way around the
two wires go.
9
INSERT THE IC INTO THE HOLDER
The ICs can now be put into the holder ensuring the
notch on the chip lines up with the notch on the
holder. IC HCF4071 should go into U1 and IC HCF4081
should go into U2.
10

If you wish to add a power switch, don’t solder both ends of the battery clip
directly into the board, instead:
ADDING AN ON/OFF SWITCH
Solder one end of the battery clip to the PCB,
either black to ‘-’ or red to ‘+’.
1
Solder the other end of the battery clip to the
on / off switch.
2
Using a piece of wire, solder the remaining
terminal on the on / off switch to the
remaining power connection on the PCB.
3

MECHANICAL DETAILS
CHECKING YOUR PCB
Carefully check the following before you insert the batteries:
All holes (except the 4 large (3 mm) holes in the corners) are filled with
the lead of a component.
All these leads are soldered.
Pins next to each other are not soldered together.
The shape of the transistors and thyristors match the outline on the PCB.
The notch on IC holders ICs and PCBs all match.
The flat edge of each of the LEDs matches the outline on the PCB.
The colour bands on R4 and R6 are red, red and brown.
The red wire on battery clip goes to Power ‘+’ and the black to power ‘–’.
The red wire on buzzer goes to Buzzer ‘+’ and the black to Buzzer ‘–’.
The switch with the black button is connected to Reset.
-
-
-
-
-
-
-
-
-
-
Check the bottom of the board to ensure that:
-
Check the top of the board to ensure that:
-
Dimensions in mm
43
30
12.5
60
17.5
4
4

HOW THE QUIZ BUZZER WORKS
SW1 SW2
R6
Q3
U2BU2A
U1
LED1 LED2
4.5V
0V
R4
Q2
Q1
Reset
The quiz buzzer is based around two
types of logic gates. There are two
AND gates and one OR gate. Let’s first
examine gate U2a. One input of the
AND gate is connected to the push to
make switch SW1 on the left of the
circuit. These are the switches used
by the quiz contestants.
The input on the AND gate which this
switch is connected to is normally in a
‘low’ state (when the button is not
pressed). By pressing the button the
input to the AND gate is connected to
V+ taking it ‘high’. The other input to
AND gate U2a (that not connected to
the switch) is held ‘high’ when the
circuit is reset. Therefore by taking the
switch input ‘high’ both inputs to the
AND gate will be ‘high’ and therefore
the output will go ‘high’. This causes
the gate of thyristor Q3 to go high.
This turns it on allowing electricity to
flow through it turning on LED1. As a
result of this the anode of the thyristor
will be at a ‘low’ voltage. This thyristor
stays latched even if the switch is
released. As the anode of the thyristor
is connected to an input of U2b it
means that the output of that AND
gate can not go high until the circuit is
reset. The Other switch works in the
same way with AND gate U2b.
The circuit is reset by putting the
thyristors into a non-latched state,
this is happens when the push to
break switch is pressed and the
voltage across the thyristors is
removed.
When either the output of gate U2a
OR U2b is ‘high’ the output of U1 (OR
gate) will be ‘high’. This causes the
transistor Q1 to turn and the buzzer to
sound.

Two people (or two teams) can used the
quiz buzzer to show who pressed their
button first. When the button is pressed
the buzzer sounds and either the red or
green light is illuminated to show who
was fastest. This project is brilliant for
learning about a wide range of
electronic parts.
For more information on RoHS and CE please visit kitronik.co.uk/rohs-ce. Children
assembling this product should be supervised by a competent adult. The product contains
small parts so should be kept out of reach of children under 3 years old.
WARNING: Contents may inspire creativity
0845 8380781T:
www.kitronik.co.ukW:
[e-mail]:
TOOLS REQUIRED:
- Soldering Iron
- Solder
- Wire Cutters
- Wire Strippers
KIT REQUIRES
3 x AA Batteries
STOCK CODE
2116 or 1016 (Retail Version)
INSTRUCTIONS:
This booklet contains build instructions
and a circuit explanation. For more
detailed resources please visit our
website www.kitronik.co.uk/2116
Designed & manufactured
in the UK by
Kit of
parts
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