# How to solder PCB?

I have maybe question because of my first PCB I soldered yesterday.

I used a 2x8 cm PCB, and this is the circuit I did:

            A         I   J   K   L   M   N

o--      -D1-—o--SW1--o---VCC o
|         D1     SW1      REL
Ad 5V   X---o         D1  D2-SW1--o---CH1 o
|   D2      |   REL
X   o         R1  D2—-R2  R3  GND o
R1      R2  R3  |
X   o         R1  o   R2  R3  o   o
R1      R2  R3  |
Ad GND  X---o         R1  o   R2  R3  o   o
|         R1      R2  R3  |
O--      -R1--o---R2--R3--o   o

• A .. N are the columns of the PCB, I leave column B..H free for future additions (the VCC and GND lines are connected)
• Dx are diodes, Rx are resistors, SW1 is a pin header for a switch and column - Column N is a pin header for a relay (module).
• X are the connection 'terminals' of the PCB (on the left/right side, right side is unused)

However, during soldering, I noticed a few things and wonder what is best:

• I had a lot of soldering to do from one hole to an adjecent hole, and sometimes more like the connection between SW1, CH1 and R3 (colums K, L, M). Since I used just soldering, it was like a big 'solder blob' ... is it best to use some small wire instead? It will be very tiny wire(s)
• For the long VCC and GND lines I used a wire which I bent (see column A and the Xes) and soldered them on various places.
• I noticed it was very hard to solder adjecent lines (components close together), but leaving more space needs longer lines (and have to use wires instead of just solder?)

What are guidelines to make those 'interconnections' between adjecent holes?

And a side question: this is a 'double' sided board, but I don't see what it means, since the holes are connected anyway from the top and bottom side after soldering. Or do I miss something here?

Update 1

There was a discussion about my 'ascii' notiation... I will explain it a bit below.

The problem is, that I never have soldered on a proto/pcb/stripboard whatsoever, only did breadboarding. Since I want to be sure I don't mix up lines/columns, I like to make it visible before I start (and to see it fits).

I will leave the ASCII text above, however, to make it clear, I thought it's better using Excel. I also spaced out the colums more, so it's easier to solder.

The result is below.

• What kind of notation is this? Is this common? Should I be able to read it as engineer? Mindblown – Atizs Mar 1 '18 at 12:15
• What's wrong with the site's built-in schematics tool? You can still use it to model a physical PCB, with some care. Better than this crazy ASCII anyhow :) Notably, diodes have polarity. – Lundin Mar 1 '18 at 12:25
• @Lundin don't fully agree, I'm pretty impressed with that ASCII representation of the board :) What I think would illustrate this nicely would be a close-up photo. – Marcus Müller Mar 1 '18 at 12:28
• Ahh I see.... I think the answers are sufficient then, I wouldn't have much more to add. Could have used a picture of the board to give us a better idea! – MCG Mar 1 '18 at 13:07
• I may be dumb, but your question was completely unclear until I read the answers. A picture was indeed mandatory, or at least a word actually describing the kind of board you were soldering on. Something like "protoboard", "veroboard", or "stripboard"... This is really a missing key information in your description. – dim lost faith in SE Mar 1 '18 at 13:33

## 4 Answers

And a side question: this is a 'double' sided board, but I don't see what it means, since the holes are connected anyway from the top and bottom side after soldering. Or do I miss something here?

Yes, the green PCBs have their holes connected on both sides, before and after soldering. Calling it "double sided" is very misleading, but "true" in some sense.

This question will gain several opinion-based answers, anyhoo... disregarding that, this is what I recommend. Might be interesting since I use the exact same boards as you.

larger image

Circuit I made and used as blueprint (ish)

(Ring inverter with LEDs on the other side)

As you can see, I don't limit myself only to the plane of either side, I also go up a couple of millimeters and use that space as well. The metal pieces are from trimmed LED legs and large round resistors - no, I haven't ruined tons of LEDs so I can have small legs that work great with soldering. I simply don't throw away the legs of LEDs, I reuse them and cut them accordingly.

larger image

Circuit I made and used as blueprint

(Half bridge)

But using regular uninsulated copper wire works great too. Notice how I use the holes as a meeting point for two or more components. You usually don't need to space things apart. SOT-23 is great for 2.54 mm spacing.

(Modified version of this one that actually worked IRL)

I assume you are going to work with ICs - use their legs as well.

larger image

Circuit I made and used as blueprint

It's ugly, but it's your ugly thing. And you can't say that something you made is ugly, therefore it's handsome.

You probably cannot see it, but legs 3 and 5 are connected underneath the IC and soldered. (IC = LM393)

On the other side there are two transistors, and again I use the holes as nodes / meeting points. I rarely connect pins to different holes and then bridge the connection.

• Thanks, your answer to the side question makes me this as accepted answer, since it also answer my questions about the spacing/wires/interconnections mostly. I have to check further into it. Btw, very nice how you use SMD technology, saves a lot of space, although I don't feel confident enough so I stick with through hole parts for now. For my current 'hobby project' I don't need ICs but my big one (if I ever finish) will have 5 or more ICs. Nice soldering too, mine looked much more messy. – Michel Keijzers Mar 1 '18 at 14:03
• Circuit anti-patterns... – Graham Mar 1 '18 at 14:58
• I would avoid SMD components for these kind of hand-made prototypes. Through-hole components only build height really, as you can place resistors etc vertically as well as horizontally. But they are so much easier to work with and the end result will therefore have better quality. – Lundin Mar 1 '18 at 14:59
• First thing is that all this uses huge amounts of solder, heated for a long time. This is precisely how you go about getting dry joints, if that's the aim of your assembly process. If the aim of your assembly process is to create electrical connections, it's rather less successful. This entire post should be used as an example as how not to solder. – Graham Mar 1 '18 at 15:02
• As Lundin says, you have a board with through-holes, so through-hole components are the best choice. They are more mechanically secure, and less likely to be overheated by applying the iron for too long. They also inherently give you a way of connecting each end of the component between places. – Graham Mar 1 '18 at 15:06

is it best to use some small wire instead?

Yes, definitely. "Solder blobs" tend to get bad over time. Or use the solder-tinkerer's all-time favourite: cut-off through-hole component legs. They are awesome for such purposes, if you don't need/want the isolation provided by a wire.

Regarding the nature of the PCB, there's different kinds, either with pads (that may or may not connect to both sides) or with "copper lines", where all holes along one row are connected.

Which kind to use mostly depends on the circuit, and on personal preference. The version with "lines" is convenient when tinkering with through-hole ICs, but in the general case I personally prefer the version with "pads", as that gives more freedom. Often when building lab stuff you need to modify something, and it is convenient to do so without having to cut and carve in the actual PCB.

• I have so far only the green ones, and indeed it makes it also be able to make smaller circuits/area. I hope I don't need to modify something, otherwise I better start over again. – Michel Keijzers Mar 1 '18 at 13:00
• +1 for making me realize the kind of board OP was soldering on. Honestly, I haven't been able to understand what was asked. Congratulations. – dim lost faith in SE Mar 1 '18 at 13:29
• What is the official name for the green boards? I thought these are called PCB boards and the born you showed stripboards. – Michel Keijzers Mar 1 '18 at 13:39
• @Michel To my mind, neither of these are really Printed Circuit Boards (PCBs) in the normal meaning of that phrase - there's no real application-specific circuit printed on those boards. They are varieties of "prototyping board" one is stripboard (there is a brand called veroboard whose name people often use rather generically). The other are often just called protoboards or "prototyping boards". Boards without copper plating around the holes are sometimes called perfboard. – RedGrittyBrick Mar 1 '18 at 14:54
• @MichelKeijzers The top one is "matrix board", the bottom one is "stripboard", at least in the UK – MrZebra Mar 1 '18 at 15:56

As you noticed the solder blobs look real messy.

Using wires with a plastic coating is problematic and too much work unless you have large distances. You have to cut the wire to length, strip the ends and hope you didn't cut to short or long.

What I recommend is Magnet wire. Which is wire that has thin varnish. Usually (and you want that) the varnish is heat sensitive. So just by touching the end with the soldering iron for a few seconds the varnish disappears and you get blank wire at that point.

Using Magnet wire you can simply solder on the wire and cut the ends after soldering and you don't have to care about causing a short when the middle of the wire touches anything else.

• Thanks for this tip, I never heard about it, and seems what I can use (since I need to make quite some splits). – Michel Keijzers Mar 1 '18 at 13:01
• @MichelKeijzers Magnet wire is the same as "koper lakdraad" – Decapod Mar 1 '18 at 13:32
• @Decapod ok :-) I will check where I can get it cheap (Conrad is nice but normally it adds already 5-10 euro shipping cost, making something for a euro too expensive). – Michel Keijzers Mar 1 '18 at 13:33

I sometime use silver wire or (insulated or not) copper wire for the interconnections. When the copper pads you want to connect are directly next to each other you can use a 'solder blob' (2.54 mm grid or less). In my opinion it looks much cleaner if you use a silver wire which you stretch a little bit (make it straight) for wider interconnections.

Double sided means that you have copper pads on both sides. The advantage over pads on just one side is that you are able to solder on both sides. With one sided you can only place your components (throughhole leaded) on one side.

This is the case for printed circuit boards with a point grid or another grid.

• why (uninsulated?) silver wire or insulated copper wire? I mean, why not (uninsulated) copper wire? I don't see the difference between silver or copper wire. – Michel Keijzers Mar 1 '18 at 13:04
• True, you're right. There is not much a difference and it's cheaper. Just forgot it. – NeverToLow Mar 1 '18 at 13:08
• Ok, still upvoted, the double sided part I wasn't fully aware about. – Michel Keijzers Mar 1 '18 at 13:11