View Full Version : Basic Soldering Questions
Hello,
I have a project from school that requires some soldering. My only experience with soldering so far is connecting two 12 gauge wires together, so I was hoping I could get a little advice.
To start with, I plan on using this PCB kit to make my circuit.
http://www.radioshack.com/product/index.jsp?productId=2102870&cp=2032058.2032230.2032265&parentPage=family
Does anyone have any experience with anything like this? I gather I will trace the outline of my circuit on the board and then use the included acid to etch away everything else. I figure this will be the easy part.
Once I have the board done, now I need to solder two capacitors, a couple of resistors, and 6 take-off wires that will connect to other parts of my device. I plan on making large "pads" where I intend to make each soldered connection, and then soldering directly to these pads. I will make the pads directly onto the PCB, just like any connection.
So, does anyone have any advice about the best way to do this? I believe I have all the supplies I need (soldering iron, flux, solder) I’m particularly concerned about burning a capacitor, so is there anyway I can prevent this?
I realize that this doesn't deal directly with volt moding, but the technique (albeit cruder) seems to be similar, so thanks for putting up with a soldering noob.
Below is a picture of my planned setup. The black dots represent the pads, and the dotted lines represent the PCB board connections.
funnyperson1
11-29-06, 05:30 AM
What I like to do is melt a little bit of solder onto the pads first, and then heat that up as I drop the SMD component into place.
Are those capacitors SMD? If so the pads look a little far apart.
zexmarquies01
11-29-06, 05:38 AM
honestly, its really hard to burn a capacitory. or any component, thats not extremly sensitive to heat.
Basicly, do NOT cut the leads on the capacitor. Put them through, on the PCB board where they need to go.
then, Bend the pins flat agenst the board. That way, you can flip the PCB board over, without the capacitor ( or any other compoent ) falling out.
Rasin-core solder is great. has flux in the core of the solder. But if you don't have any, put some flux on the spot where you tend to solder.
Then, put the tip of the iron on the PCB/ leads of the component, at a 45 degree angle.
Then, take the solder, and feed it into the tip of the iron, with the solder again at a 45 degree angle.
then, let it cool for about 15 seconds ( honestly, it will cool in about 5 ). the, take some small wire cutters, and cut off the ends of the leads that are sticking out, at the solder point, leaving nothing sticking out, except the solder connection.
do the same for all the other components on your board.
ALSO, make sure you put the capacitor in correctly. Notice one side of the capacitor will have a stripe going down it with " - " signs in it. Obviously, thast the negetive side.
and in my electronics class, I once had to make my own PC Board. Aargg, making the thing, and having it come out correctly was more of a Pain in the butt, than ANY soldering i'v ever done.
zexmarquies01
11-29-06, 05:45 AM
quick question....
Whats that supposed to connect to? I know thats where one of your Wires will hook up to, but...whats the use of that contact point, if its not connected to anything else in the circuit?
Shall i ASSUME that is supposed to connect to the resistors that you have connected in a series circuit?
from what i'm seeing, The power input is the contact pads on the right. The two out-puts are on the top and left. but god knows i'v been wrong thousands of times in the past....
SolidxSnake
11-29-06, 07:02 AM
zex: your first post is a little wrong. He's not using a hole-through board. He's making it all SMD. Also, when you're soldering, you're not supposed to fold the leads flat against the board. just a helpful hint ;)
OP: I'd etch the board the way you have it, and then drill holes where your components and wires will go. That would make your job much easier.
You're right with the money on etching the board. You need to heat up the liquid with a glass aquarium heater (don't try a metal one... it'll dissolve, literally) in a glass or plastic jar.
This is supposed to be a rechargeable flashlight. The leads on the left attach to a DC generator and a diode, the leads on the top attach to a switch, and the leads on right attach to an LED. I know it's a little weird having a DC parallel RC circuit, but it works for what I need. The reason there are two capacitors in series was that I needed one 4.5V 25F capacitor, but I could only get two 2.3V 50F capacitors. I've tried this all out in a breadboard and everything works fine.
Also, it is not drawn to scale. They are rather big capacitors (7.5mm lead spacing)
How would it make my job easier to drill holes in the board, and then solder? I'm a bit confused by what you mean by this.
What does SMD mean?
EDIT: I just noticed i didn't finish my circuit. Here is an updated copy. Yes, the leads on the left connect in parallel with the capacitors, and the resistors.
funnyperson1
11-29-06, 11:25 AM
This is supposed to be a rechargeable flashlight. The leads on the left attach to a DC generator and a diode, the leads on the top attach to a switch, and the leads on right attach to an LED. I know it's a little weird having a DC parallel RC circuit, but it works for what I need. The reason there are two capacitors in series was that I needed one 4.5V 25F capacitor, but I could only get two 2.3V 50F capacitors. I've tried this all out in a breadboard and everything works fine.
Also, it is not drawn to scale. They are rather big capacitors (7.5mm lead spacing)
How would it make my job easier to drill holes in the board, and then solder? I'm a bit confused by what you mean by this.
What does SMD mean?
EDIT: I just noticed i didn't finish my circuit. Here is an updated copy. Yes, the leads on the left connect in parallel with the capacitors, and the resistors.
SMD components are "Surface Mounted Devices" the little gray/brown resistors on a motherboard are examples of SMD components.
If your capacitor has leads then its not an SMD device. Normally a PCB with that type of capacitor on it will have a drill through that you stick the leads through and can solder from the bottom. I see that the kit you are using comes with a drill bit, but I am not sure how you are to go about drilling and having the connection go through to the bottom like a normal PCB.
SolidxSnake
11-29-06, 02:49 PM
SMD components are "Surface Mounted Devices" the little gray/brown resistors on a motherboard are examples of SMD components.
If your capacitor has leads then its not an SMD device. Normally a PCB with that type of capacitor on it will have a drill through that you stick the leads through and can solder from the bottom. I see that the kit you are using comes with a drill bit, but I am not sure how you are to go about drilling and having the connection go through to the bottom like a normal PCB.
Correct.
What you want to do on the PCB is first draw your circuit on the copper side of the PCB. Where you want the leads of your components to go, make circles (should be dots in the kit that you use for those). Then, you etch the board (heat the chemical, I don't remember the specific one used, and then soak the board in it for several minutes). After the board is etched, remove what you drew on the board (either scrape it off, alcohol, acetone, etc.), and then drill with a small drill bit where the leads of your components are to go. Then you insert the components through the side of the board without the copper (so the leads are sticking through on the copper side), and solder.
What are the advantages of using the thru holes as opposed to soldering directly onto the pads?
SolidxSnake
11-29-06, 03:40 PM
What are the advantages of using the thru holes as opposed to soldering directly onto the pads?
Well, are you using SMD components or components with leads? If you have leads, you should be using holes.
Here is a picture of the capacitor I'm using. I guess this means I need to drill the thru holes. One other question though: What does an SMD component look like?
SolidxSnake
11-29-06, 05:07 PM
http://www.fastcomponents.co.uk/images/smd-002.jpg
http://futurlec.com/Pictures/SMD_Electrolytic_Capacitor.jpg
Look at your motherboard, there's bound to be hundreds of them.
Trust me, drilling holes will be MUCH much easier to solder. Not to mention much sturdier as well.
jdrake90
11-29-06, 05:12 PM
Listen to Snake... he's the smartest 13 year old on this forum... gives me the creeps;-)
Jdrake90
Sorry, one last thing. Should I use thru holes for the connecting wires as well?
SolidxSnake
11-29-06, 06:34 PM
Sorry, one last thing. Should I use thru holes for the connecting wires as well?
I sure would. I should think it would give them more stability.
Thx for the kind words, Jordan (That's your name, right?). :)
speed bump
11-30-06, 11:51 AM
Just solder everything point to point if thats all the circuit you are building.
With that layout you have I would just go to radioshack and pick a brown PCB board with all the holes evenly spaced and drilled. Lay your components out and solder em down on the backside. Its faster and easier to build and unless this is a project that requires you to etch the PCB its really not worth it for that small of a circuit.
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