beginner question - batteries and LEDs

[youngstownguitar]

I'm still learning.

If you have a layout for a pedal that works with a DC Jack and a battery clip but you want to remove the battery clip can you just leave it off?  Or will that screw up the circuit and you should replace it with something else?

Regarding LEDs, I see one end is longer then the other but which is positive and which is negative?

Is a good path for setting up a LED basically:
switch - LED- resistor - 9v   ?

I know these questions arent very complicated but I seriously spent hours trying to figure them out- and info you guys could share would be appreciated- thanks a lot

[Jhouse]

Nope, You can't completely forget about the battery clip and nothing bad comes of it. You can also use a mono jack for the input if you aren't worried about power switching.

As for the LED, it's just a good habit to have the longer side (considered the positive I guess) side going to the DC jack, but always solder a resistor in between them, a 2k2 or 4k7 works nicely.

[youngstownguitar]

Ok so what can I do to safely remove the battery clip?

This is my layout so far:
http://s640.photobucket.com/albums/uu130/surgerymixer/?action=view&current=goatlegdrawing.jpg

[PRR]

> the battery clip can you just leave it off?

Yes.

At least on the plan you posted.

I will point out that a battery clip will seem cheap the day your power supply gives trouble and you need to get the pedal working NOW.

> Nope, You can't completely forget about the battery clip and nothing bad comes of it.

I'm not following this sentence. Maybe the internet scrambled what you typed?

[PRR]

> which is positive and which is regular?

"Regular"?

Anyway... I've worked with LEDs since they came down below $5 each (around 1979) and _I_ can never remember which way they go. Generally when I know it's gotta work, I try one way, then the other. (9V reverse polarity through the usual resistor does no harm to an LED.)

Important Lesson: EXPERIMENT! Get a battery and clip(!), resistor, LED. Connect together. When it works, make a note and pin it over your bench.

[youngstownguitar]

> which is positive and which is regular?

"Regular"?

Anyway... I've worked with LEDs since they came down below $5 each (around 1979) and _I_ can never remember which way they go. Generally when I know it's gotta work, I try one way, then the other. (9V reverse polarity through the usual resistor does no harm to an LED.)

Important Lesson: EXPERIMENT! Get a battery and clip(!), resistor, LED. Connect together. When it works, make a note and pin it over your bench.

Sorry I meant which way is positive and which way is negative.
thanks for the info

[Top Top]

The longer leg on the LED gets connected to the positive. I am terrible at remembering these types of things, but somehow I remember that one.

Polar caps, on the other hand, I can never remember if the scooped side in a schematic is positive or negative.

[youngstownguitar]

Ok so let me get this straight.  Going by the layout I posted, if I want to add LEDs It would go like this:

From the spot labelled "9V" the red wire would go to the short side of the LED.  Then the long side of the LED would connect to a 4k7 resistor. The resistor would connect to the tip of the DC Jack.

And this method would work for each PCB/LED correct?

[youngstownguitar]

anyone?

[Govmnt_Lacky]

A few things:

1) On your LED, the LONG leg should be connected... via a pull down resistor.... to your +V supply (9V). The SHORTER leg should be connected to ground.

2) It appears that both boards you are using ALREADY have provisions for an LED (according to your diagram above) so all you should have to remember is that the LONGER leg of the LED should go to the + or positive side.

3) You should ground the sleeve of your input jack. Some people let the enclosure do the grounding however, if that jack comes loose you will regret it! 

Good Luck 

[Jhouse]

Nope, You can't completely forget about the battery clip and nothing bad comes of it.

Wow, fail post. That should be can not can't.

Anyway, as Govmnt put it, you already have provisions for an LED on the board and the wiring looks just fine.

You should ground the sleeve of your input jack. Some people let the enclosure do the grounding however, if that jack comes loose you will regret it!

I like to use shielded wire for my input to the board and from the guitar. It really cuts out on most if not all of the hum and I ground the shielded part to the enclosure generally. It really just kind of depends on my mood.

[youngstownguitar]

A few things:

1) On your LED, the LONG leg should be connected... via a pull down resistor.... to your +V supply (9V). The SHORTER leg should be connected to ground.

2) It appears that both boards you are using ALREADY have provisions for an LED (according to your diagram above) so all you should have to remember is that the LONGER leg of the LED should go to the + or positive side.

3) You should ground the sleeve of your input jack. Some people let the enclosure do the grounding however, if that jack comes loose you will regret it! 

Good Luck 

Ok so if I use the existing spots on the board for the LEDs which side means positive and which negative?  I see one side is rounded and one is square but which is which?  And if I use them do I need a resistor as well?

Also, what is the best way to ground the sleeve of the input jack?  Can I just connect it to something else that is grounded like the sleeve of the output jack?

[DiscoVlad]

The longer leg on the LED gets connected to the positive. I am terrible at remembering these types of things, but somehow I remember that one.

Polar caps, on the other hand, I can never remember if the scooped side in a schematic is positive or negative.

The IEC symbol has a +, which makes things much easier to remember.

[Govmnt_Lacky]

Ok so if I use the existing spots on the board for the LEDs which side means positive and which negative?  I see one side is rounded and one is square but which is which?  And if I use them do I need a resistor as well?

You should refer to the schematic for the circuit. I AM ASSUMING that if the provisions were made to put the LED on the circuit board, that the pull down resistor is also on the board however, VERIFY AGAINST THE SCHEMATIC FIRST!

Also, what is the best way to ground the sleeve of the input jack?  Can I just connect it to something else that is grounded like the sleeve of the output jack?

Yes! 

If you need more help with these questions, posting a link to what layout/schematic you are using would help.

[edvard]

...
Ok so if I use the existing spots on the board for the LEDs which side means positive and which negative?  I see one side is rounded and one is square but which is which?  And if I use them do I need a resistor as well?
...

Even with both legs clipped and the collar sanded off, you can always find the negative terminal as long as you can see inside the thing.
Look for the part that looks like a little cup on a shelf.
It's called the "Anvil" here:
http://en.wikipedia.org/wiki/File:LED,_5mm,_green_%28en%29.svg

[youngstownguitar]

You should refer to the schematic for the circuit. I AM ASSUMING that if the provisions were made to put the LED on the circuit board, that the pull down resistor is also on the board however, VERIFY AGAINST THE SCHEMATIC FIRST!

If you need more help with these questions, posting a link to what layout/schematic you are using would help.

The thing is, Im not really using an exact layout here- kind of making it up as I go.

I am planning on putting two pedals together- both from madbean- the zombii version 4 and slambox version 3
links to both layouts can be found here:
http://madbeanpedals.com/projects/index.html
I cant just post exact links because the main links he has up are for newer versions of these boards.  You have to click on the right where it says "download" and the older versions download.


Also, it looks to me like I dont need to add a resistor to the LED as long as I use the on board spots for them.

[PRR]

> The longer leg on the LED gets connected to the positive.

Thanks.

> Polar caps, on the other hand, I can never remember if the scooped side in a schematic is positive or negative.

This one, it does help to be old. An electrolytic is an aluminum can with stuff inside. One end of the cap IS the can! The inside is brought out through a tar or rubber seal.

Can is round.

Curved line is the "can".

Moving up to recent decades.....

The direct descendant of the big old cans is the axial electrolytic.



Look close. The positive lead comes through the dimpled-in rubber seal. The negative lead is just butt-welded to the CAN. The can is round, is the curved line on the symbol.

Compact PCBs want both leads on the same end, "radial". I dunno where the NEGative lead really connects to the can because we see it after it comes through the rubber seal. So you gotta find the polarity mark, then think-back to axials and can-caps.

[petemoore]

  Starting with 3k3 or so, the led, and the battery.
  Pinning the resistor lead to an LED lead with one hand, connecting the LDR>LED to a battery [then other way around when it doesn't light]...kind of like eating with chopsticks, careful not to short the LED across the battery.
  Double checking polarity and brightness=resistor.
  Then twisting the resistor lead with the LDR - lead, double checking polarity, installing.
  Either side of the LED is fine place for the resistor, I chose - so I could be consistant and remember, and have the R lead go right to the switch.