Questions Re Building Circuits From PCB Layouts

[jzilla]

hi,

i'm trying to wrap my head around building a circuit (without etching) on perf or vero board from a PCB layout.  would someone mind answering these questions?

(using this layout as a reference: http://www.tonepad.com/getFile.asp?id=31)
- what is the purpose of the blocks?
   eg the lower left corner
- why are some points square and some circular?
- when should i use veroboard vs perfboard?

i'm sure i'll have others but hopefully this can get me moving in the right direction.

very much appreciated.  this place is an amazing resource.

-j

[Top Top]

I have only done perfboard myself but from what I have seen with veroboard, you should use a layout that is designed for it if you are going to use it.

Vero uses strips of already applied copper in rows that you solder components to and occasionally have to cut.. Perf is just a board with holes in it. Perf is more flexible in that way, but a little more complicated in that you have to jump with wire from component to component.

I can't open the layout you lined to because I'm on a mobile device but hopefully someone else can help you on that.

[doitle]

Alright...

The blocks you refer to: Do you mean as in the entire right hand side of the board? There is a large dark space. Also in the bottom left as you mentioned and in the top left there is a small one. Those are a ground plane. Or even just a ground pour since it's not really a plane persay... That is a large area of copper on the PCB that connects many ground nodes in the circuit. Having a larger grounding area just helps decrease noise a tad and can sometimes make laying out the PCB simpler.

In this circuit it looks like square pads are just the connections to the outside world. (Barring the pots) These are all of the connections that run to the battery and to the switches.
In general as far as Circular Vs. Square, I'm almost positive it is to help you notice that the part in question is polarized. You might have a capacitor where one pin is square and one is round and the square might designate where the negative side is or some other mechanism. Somebody might be able to tell you definitively but I'm fairly certain that is the reason for some holes being square. Also for DIP ICs a lot of times pin 1 will be designated by a square hole.

I dont know for sure which you should use but it seems to me that if you lay out a PCB with a similar grid spacing as the spacing of holes on a perf board you should be able to make a functionally identical board with identical parts placement. I believe frequencycentral might do this as some of his perfboard circuits look almost like a PCB with the nicely placed runs of solder and tight part placement. I suppose you should be able to do nearly anything on vero that you could do on perf with some number of trace cuts. Still perf would make more sense to me if you want to work directly from a PCB layout.

[Top Top]

I dont know for sure which you should use but it seems to me that if you lay out a PCB with a similar grid spacing as the spacing of holes on a perf board you should be able to make a functionally identical board with identical parts placement. I believe frequencycentral might do this as some of his perfboard circuits look almost like a PCB with the nicely placed runs of solder and tight part placement. I suppose you should be able to do nearly anything on vero that you could do on perf with some number of trace cuts. Still perf would make more sense to me if you want to work directly from a PCB layout.

You definitely can use perfboard to do a PCB layout... That is usually how I place parts for circuits - by looking at PCB layouts, placing parts, and recreating the copper traces with wires. Really, you could do a stripboard layout on perf as well, just putting wires in place of the strips of copper shown on the layout.

The other way around (trying to do a PCB layout on stripboard) could cause problems, as stripboard is layed out in straight rows. You would likely have to do a lot of trace cutting, which would negate the intended ease of use of stripboard.