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Topic: Legs of components not long enough, what do you do? (Read 1 time) previous topic - next topic

Foolios

I have a couple of components that the ground leg won't make it to the connection point on my breadboards/circuit boards. The legs are just too short. What can you do when this happens? I soldered some wires onto the legs of a resistor, led, and a capacitor and now my project doesn't work.
What could be going wrong or how did you make your too short connections work?

jackrae

If you are using a breadboard you plug the components into available points then use jumper links to connect to the desired locations.  This works OK for DC systems and low frequencies but if working at RF/VHF/UHF you need extra care due to capacitance and inductance introduced by the links.

Foolios

When I transplant to the printed circuit board I get from RadioShack. There isn't enough holes in a row but there are single holes all over. How do I connect those singles to the rows? I see they have Bare Paint and I was thinking of using that to connect a hole to a row.
How do you go about solving that problem?

Docedison

Having some skill with a soldering iron and some short pieces of wire I usually solder the wire pieces to the "Short" leads and then use them. The nice part of this technique is that the leads are always the right length...

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

Foolios

Ok, I'll keep trying. Do you use heatshrink or anything?

Foolios

#5
Oct 19, 2013, 08:25 pm Last Edit: Oct 19, 2013, 08:27 pm by Foolios Reason: 1

If you are using a breadboard you plug the components into available points then use jumper links to connect to the desired locations.  This works OK for DC systems and low frequencies but if working at RF/VHF/UHF you need extra care due to capacitance and inductance introduced by the links.


One concern I am having with this is when I use capacitors.
For making the Breaduino it requires that a capacitor is connected from pin 9 and 10 to grounds via the capacitor. And then the 16mhz chip is supposed to be placed in between them at pin 9 and 10.
http://arduino.cc/en/Main/Standalone
So if I were to put the capacitors on a different part of the board and jumpered them from ground and then to the row of the pins. Would that still perform in the same way or would the crystal no longer be between the caps and the pins of the Arduino?

I guess if I understood why the crystal is supposed to be between, it would help.

Docedison

#6
Oct 19, 2013, 09:14 pm Last Edit: Oct 21, 2013, 12:26 am by Docedison Reason: 1
You can place the crystal wherever you like, it isn't uncommon to have a cm between the crystal/caps and the processor.
While it's better to put the crystal right on the processor an added centimeter or two (no more than 2 cm total) won't materially affect the operation of the crystal in my experience.

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

Foolios

#7
Oct 19, 2013, 09:37 pm Last Edit: Oct 19, 2013, 10:06 pm by Foolios Reason: 1
That's valuable to know.
I can place the crystal close to the chip no problem.

How do I place a capacitor in a blank area of a breadboard and jumper to and from it while making it still effective? Or does it HAVE to be inline(directly in the row) with the component?

MarkT

Try it and see - some stray capacitance isn't likely to hurt a crystal because it already
has 22pF to ground on each leg, but the stray inductance may be an issue.  Depends on
the frequency, the strength of the oscillator, nearby interference, various factors.
[ I won't respond to messages, use the forum please ]

dc42

The positioning of the 22pF caps associated with the crystal is not critical.  Follow the advice already given. The positioning of the 0.1uF cap between Vcc and Gnd is more important. Place it it directly between the Vcc and Gnd pins of the atmega328p, right over the top of that chip.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

fungus


When I transplant to the printed circuit board I get from RadioShack. There isn't enough holes in a row but there are single holes all over. How do I connect those singles to the rows? I see they have Bare Paint and I was thinking of using that to connect a hole to a row.
How do you go about solving that problem?


When you put a comonent leg through a single hole you can bend it over to touch the hole next to it. This allows you to create your own "rows".
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

Foolios

Oooh, so put a leg of two components in the same hole on the circuit board and/or attach holes via legs.

I love it, thanks for the tips/advice!

fungus


Oooh, so put a leg of two components in the same hole on the circuit board and/or attach holes via legs.


Usually you put them in adjacent holes and bend one of the legs so they touch underneath.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

Foolios

Great! That'll work too. You get a Karma Point! =)

Foolios

#14
Nov 23, 2013, 08:53 pm Last Edit: Nov 23, 2013, 08:58 pm by Foolios Reason: 1
I began having problems with my projects(using breaduino) even when placing them back onto the breadboard as I was trying to figure out how to jumper the capacitors(for crystal clock) -due to the short leads.
Soldering wires and using jumpers for some reason causes the lcd to not initialize. - I would place the crystals in their own rows then jumper them to the crystal and ground.
Once I placed the two capacitors right next to the crystal(pins 9,10) and directly to ground(for my breaduino projects) the lcd would initialize again.
I am hoping that now when I solder this project onto a board I will be able to resolve that issue with the techniques discussed in this thread.

I sure would like to understand why the capacitors and crystal are so picky about placement with regard to each other.

posted by dc42
"The positioning of the 0.1uF cap between Vcc and Gnd is more important. Place it it directly between the Vcc and Gnd pins of the atmega328p, right over the top of that chip."

Should I add this to my breaduino? I didn't see any instructions on doing this in either of the two tutorials on how to make a breaduino.

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