Need a little LED Help from my DIY friends

[soupbone]

I've got a NTE 30043 Super Bright,Clear Blue LED.I found a cool LED+Resistor site. www.led.linear1.org/1led.wiz  There's 3 things they ask for; 1.Source Voltage 2.Diode Forward Voltage 3.Diode Forward Current  On the packaging for the NTE LED,it has some symbols.Here's the symbols; VF(forward voltage?!),VR(voltage resistance?!),PD(?),lF(forward led current?!),lV(?) I'm wondering what these symbols mean.Also,here's the data for the led.Vf-4.0Vmax---Vr-5Vmax---PD-120mW max---lf-30mA Max---lV-3500mcd Typ

[anchovie]

Vf = forward voltage
Vr = reverse breakdown voltage
PD = power dissipation
If = forward current
Iv = luminous intensity

Don't use that online calculator though - it'll give you the resistor value for running at full brightness, which I think your eyes will dislike!

The rule-of-thumb that I use for stompboxes is to try a 2.2k for standard LEDs or a 10k for super-bright as a starting point and increase or decrease if necessary.

[GibsonGM]

Vf = forward voltage
Vr = reverse breakdown voltage
PD = power dissipation
If = forward current
Iv = luminous intensity


The rule-of-thumb that I use for stompboxes is to try a 2.2k for standard LEDs or a 10k for super-bright as a starting point and increase or decrease if necessary.

+1,000    The calculator would probably keep you safe, not destroy the LED, but won't give you what you want, I bet.

They will list a MAX forward current If  for LEDs....and that is WAY bright, ha ha.....I mean, I often just pop a 1k resistor in front of one as soon as I grab it, knowing it'll be bright but not too bright, nor too dim (if that makes sense).   The "ideal" resistor as caculated might have been HALF that 1K value!!   

I suppose the message here is that you need a lot less current thru an LED than you might think.  The bonus is, the higher your resistor, the longer your battery will last   5 to 8mA is often FINE, believe it or not! 

[bluebunny]

+2000!

This is what happens when you use a resistor suggested by these calculators:

 

[GGBB]

The bonus is, the higher your resistor, the longer your battery will last   5 to 8mA is often FINE, believe it or not! 

+1

I've actually been running the last couple of uber-bright LEDs I used at about 1mA which was a 6k8 resistor - still plenty visible but not glaringly bright as is the trend these days apparently.

[deadastronaut]

i love leds, but even i tone em down ...i test in daylight and in the dark..then settle on a value that i don't need shades for..

[davent]

I find the high brighness are a fine run well under 1mA, i've gone as high as 47k to tame them (on a 9v supply.)

[duck_arse]

me too on the +1.

[Mark Hammer]

I've noted in past my building and use of an LED-brightness tester.  I rigged up a 12-position rotary switch with a selection of resistance values from 1k up to 18k, a socket for the LED, and a 9V battery snap.  I start from the highest resistance (lowest current), plug in the LED, and work my way down until I hit a brightness level that I like.  I make note of where the "sweet spot" is in the sequence of resistor values, and use that LED with an appropriately-chosen common resistor value.  You could do the same thing with a pot, but you'd need to keep measuring with your meter.  This way, I know what the value is at each switch position.

If you've ordered a bunch of LEDs that have a known brightness and efficiency rating (e.g., 20,000mcd, 3000mcd, 600mcd, etc.), one can often make an educated guess about what value of current-limiting resistor to use.  However, I would guess that I'm not the only person here who has a little drawer marked "LEDs", and a wide assortment of units inside the drawer, with no accompanying information.  The brightness tester/adjuster is helpful for tailoring the resistor to a variety of unknown units.

[composition4]

Also, I know that people like their waterclear LEDs, but diffused LEDs are much much better for visibility in all conditions. You can run a diffused at a high current and it won't blind you in the dark, yet will be far more visible in sunlight conditions.  And you won't have to worry about the angle either, equal visibility from all angles.

Jonathan

[davent]

I've noted in past my building and use of an LED-brightness tester.  I rigged up a 12-position rotary switch with a selection of resistance values from 1k up to 18k, a socket for the LED, and a 9V battery snap.  I start from the highest resistance (lowest current), plug in the LED, and work my way down until I hit a brightness level that I like.  I make note of where the "sweet spot" is in the sequence of resistor values, and use that LED with an appropriately-chosen common resistor value.  You could do the same thing with a pot, but you'd need to keep measuring with your meter.  This way, I know what the value is at each switch position.

If you've ordered a bunch of LEDs that have a known brightness and efficiency rating (e.g., 20,000mcd, 3000mcd, 600mcd, etc.), one can often make an educated guess about what value of current-limiting resistor to use.  However, I would guess that I'm not the only person here who has a little drawer marked "LEDs", and a wide assortment of units inside the drawer, with no accompanying information.  The brightness tester/adjuster is helpful for tailoring the resistor to a variety of unknown units.

I also use Mark's tester for my random assorted collection of LED's , some use as low as 470r, some are out of sight. Switch adds a 10k in series.

[Mark Hammer]

I also use Mark's tester for my random assortment collection of LED's , some use as low as 470r, some are out of sight. Switch adds a 10k in series.

Given how LED efficiency keeps increasing, while the contents of my LED drawer don't get any younger, I'll likely have to add a switch like yours soon, too.  Good idea! 

[soupbone]

Vf = forward voltage
Vr = reverse breakdown voltage
PD = power dissipation
If = forward current
Iv = luminous intensity

Don't use that online calculator though - it'll give you the resistor value for running at full brightness, which I think your eyes will dislike!

The rule-of-thumb that I use for stompboxes is to try a 2.2k for standard LEDs or a 10k for super-bright as a starting point and increase or decrease if necessary.

Cool!Thanks!

[soupbone]

+2000!

This is what happens when you use a resistor suggested by these calculators:

 

My eyes!lol

[soupbone]

I've noted in past my building and use of an LED-brightness tester.  I rigged up a 12-position rotary switch with a selection of resistance values from 1k up to 18k, a socket for the LED, and a 9V battery snap.  I start from the highest resistance (lowest current), plug in the LED, and work my way down until I hit a brightness level that I like.  I make note of where the "sweet spot" is in the sequence of resistor values, and use that LED with an appropriately-chosen common resistor value.  You could do the same thing with a pot, but you'd need to keep measuring with your meter.  This way, I know what the value is at each switch position.

If you've ordered a bunch of LEDs that have a known brightness and efficiency rating (e.g., 20,000mcd, 3000mcd, 600mcd, etc.), one can often make an educated guess about what value of current-limiting resistor to use.  However, I would guess that I'm not the only person here who has a little drawer marked "LEDs", and a wide assortment of units inside the drawer, with no accompanying information.  The brightness tester/adjuster is helpful for tailoring the resistor to a variety of unknown units.

I also use Mark's tester for my random assorted collection of LED's , some use as low as 470r, some are out of sight. Switch adds a 10k in series.

That's cool!

[soupbone]

Thanks folks for all of the awesome ideas!

[bluebunny]

+2000!

This is what happens when you use a resistor suggested by these calculators:

 

My eyes!lol

I sold that one to a pal of mine.  He's OK with it, but his labrador hates me...        

[deadastronaut]

^  free shades with every pedal...

[soupbone]

I've got a NTE 30043 Super Bright,Clear Blue LED.I found a cool LED+Resistor site. www.led.linear1.org/1led.wiz  There's 3 things they ask for; 1.Source Voltage 2.Diode Forward Voltage 3.Diode Forward Current  On the packaging for the NTE LED,it has some symbols.Here's the symbols; VF(forward voltage?!),VR(voltage resistance?!),PD(?),lF(forward led current?!),lV(?) I'm wondering what these symbols mean.Also,here's the data for the led.Vf-4.0Vmax---Vr-5Vmax---PD-120mW max---lf-30mA Max---lV-3500mcd Typ

One other question I had was,I have a MXR Classic Overdrive(the ones the sell at guitar center),and I put a Water Clear Bright Green LED in it.It's pretty blinding.Can you solder a resistor on the back of the PCB to bring the brightness down?

[soupbone]

^  free shades with every pedal...

haha!