1. THERMOMETER PROJECT
PCB ASSEMBLY INSTRUCTIONS

2. ASSEMBLING THE PCB Hold the PCB as shown.
Now go through the components to ensure you can identify each one
Label
Component
No.
R1-6
150Ω Resistor (brown, green, brown) 6 R7
20KΩ Resistor (red, black, black, red) 1 TS
22KΩ Thermistor C) C1
1uF Ceramic Dipped Capacitor
LED1-12
3mm Red LED 12
IC1
12F675 IC
8pin DIL IC Holder
2xAA Battery Holder with leads

3. RESISTORS There are 7 resistors in all.
R1 to R6 are all 150 ohms in value. They can be placed either way round.
R7 is a low tolerance type which is blue with 5 coloured bands. It can also be inserted either way round.

4. IC HOLDER
The IC holder is for the IC. It is optional but a good idea to use it. The holder has a notch at one end.
This should face downwards.

5. CAPACITOR
There is one 1uF ceramic dipped capacitor. It has the numbers “105” written on one side.
This can be inserted either way round as it in a non-polarised type.
It will be either blue or yellow in colour.

6. LEDs
There are 12 LEDs. They must be inserted the correct way round. The LED has a flat section on the rim of the LED to denote the negative.
This is clearly shown on the PCB, and how each LED is inserted the opposite way round from the ones next to it.
These can be pushed all the way into the PCB, use a spacer (6mm) to space the LEDs far enough from the PCB to clear the other components.
6mm spacer

7. THERMISTOR
The Thermistor inserts below the IC holder. It can be inserted either way round.
The wires are long so it can be soldered some distance from the board and positioned where required.
Make sure the wires do not touch together otherwise the reading will stay at 30 degrees.

8. POWER LEADS
The power leads from the battery holder are inserted up through the large hole in the PCB marked “Wire” and then back through the holes marked “+v” and “0v”. This prevents them from breaking off. Solder these wires to the pads underneath.

9. INTEGRATED CIRCUIT
The IC can now be inserted into the IC holder. Make sure the notch on the case of the IC is facing downwards and all the pins are inserted correctly.
To ease IC insertion, carefully pinch the rows of legs inwards slightly to help align them. ICs generally have their legs set slightly apart from manufacture.