Soldering Advice for ComponentsIt is very tempting to start soldering components onto the circuit board straight away, but please take time to identify all the parts first. You are much less likely to make a mistake if you do this!
- Stick all the components onto a sheet of paper using sticky tape.
- Identify each component and write its name or value beside it.
- Add the code (R1, R2, C1 etc.) if necessary.
Many projects from books and magazines label the components with codes (R1, R2, C1, D1 etc.) and you should use the project's parts list to find these codes if they are given.
- Resistor values can be found using the resistor colour code which is explained on our Resistors page. You can print out and make your own Resistor Colour Code Calculator to help you.
- Capacitor values can be difficult to find because there are many types with different labelling systems!
For most projects it is best to put the components onto the board in the order given below:
|Connect the correct way round
by making sure the notch is at the correct end.
Do NOT put the ICs (chips) in yet.
|Resistors||No special precautions are needed with resistors.|
|Small value capacitors|
(usually less than 1µF)
|These may be connected either way round.
Take care with polystyrene capacitors because they are easily damaged by heat.
(1µF and greater)
|Connect the correct way round. They will be marked with a + or - near one lead.|
|Diodes||Connect the correct way round.
Take care with germanium diodes (e.g. OA91) because they are easily damaged by heat.
|LEDs||Connect the correct way round.
The diagram may be labelled a or + for anode and k or - for cathode; yes, it really is k, not c, for cathode! The cathode is the short lead and there may be a slight flat on the body of round LEDs.
|Transistors||Connect the correct way round.
Transistors have 3 'legs' (leads) so extra care is needed to ensure the connections are correct.
Easily damaged by heat.
|Wire Links between points on the circuit board.||Use single core wire, this is one solid wire which is plastic-coated.
If there is no danger of touching other parts you can use tinned copper wire, this has no plastic coating and looks just like solder but it is stiffer.
|Battery clips, buzzers and other parts with their own wires||Connect the correct way round.|
|10||Wires to parts off the circuit board, including switches, relays, variable resistors and loudspeakers.||You should use stranded wire which is flexible and plastic-coated.
Do not use single core wire because this will break when it is repeatedly flexed.
|11||ICs (chips)||Connect the correct way round.
Many ICs are static sensitive.
Leave ICs in their antistatic packaging until you need them, then earth your hands by touching a metal water pipe or window frame before touching the ICs.
Carefully insert ICs in their holders: make sure all the pins are lined up with the socket then push down firmly with your thumb.
What is solder?
|Reels of solder|
Photograph © Rapid Electronics
The best size of solder for electronics is 22swg (swg = standard wire gauge).