Getting ready to etch first PCB - general question

[morpha2]

So, I'm about to do my first printed circuit board using the Press-N-Peel method. I wanted to do a fairly simple circuit first, so I was planning on trying an APC that I found online (seen here).

Now, my question is, why are there the black blocks covering certain parts of the circuit layout? Compare the printable b&w layout on the left to the populated layout to the right. I've seen this in some other layouts as well. Should I just clean 'em up in photoshop or is there some purpose I'm missing?

[toneman]

The "black blocks"  are for reducing the amt of etchant required.
If the copper is covered (with black toner), it will not etch, so it saves etchant!!   
U only need to create the circuit paths. 
U can leave as much or as little of the "other copper" as U want.
Good luck!  on your first etch!!   
T

[Mick Bailey]

You sometimes see this where there are a number of common component connections, and where it's feasible to do. There are quite a few reasons for doing this, particularly in RF or high-current applications (none of which apply to this particular design). I happen to prefer this approach for my own designs, as it reduces the amount of copper that needs to be dissolved away and makes for more robust pads.

If you look at the circuit they're both the same.

The only thing is with PnP is that these areas sometimes don't 'fill' quite as well as they should. Inspect the board after peeling and touch in missing areas with a Sharpie or similar water-resistant marker before etching.

[morpha2]

Thanks! Looking closely at the circuit layout, I see what you mean.

[earthtonesaudio]

Sometimes you see this for heat dissipation as well.

[MikeH]

The amount of etchant it saves is pretty minimal (unless you're making a hundred-thousand boards or so  ) but the real convenience to guys like us, is that it takes a lot less time for the etching to complete.

[Michael Allen]

i just etched a pretty large circuit board in about 1 minute with HCl and H2O2. It was for a phaseur, double sided, with ground pour on both sides. This means that there is only a thin outline around each trace and most of the copper is left unetched. went real quick...

with boards like that size it probably won't make a huge difference but with double sided boards it's really helpful

[morpha2]

Hey, thanks again for all of the input. The board came out pretty nicely.

Only one problem now: the circuit makes the right sounds, but the LED doesn't light up when it's turned on. Any idea what went wrong?

[Electron Tornado]

First see if the LED is installed correctly.

If that checks OK, check to see if there is voltage getting to the LED. Is it the correct amount of voltage?

If there's no voltage, check the LED circuit for continuity.

If the LED is in correctly and it's getting the correct voltage when it should, try a different LED.


Hope this helps. By the way, the PC board looks great.

[morpha2]

Thanks man! I don't know why I didn't try this in the first place, but I swapped in a different LED and it works perfectly now. Guess I had a bad one.

[SonicVI]

Nice Big Star related name Morpha2.   

[oldrocker]

It turned out nice.  Although I perfboarded mine I found the cigarette case a nice enclosure for it.

[flo]

Cool enclosure, creative! 

[oldrocker]

Thanks.  The red LED is in the middle of the letter A.