Typical IR LED; what is the voltage drop & max current?

Status
Not open for further replies.

William At MyBlueRoom

New Member
Seems I'm looking in the wrong place on Google for IR LED datasheets. I do recall they can be used at upto 100ma (50% duty cycle?) are they 1.2v drop? 1.7v?
 

Attachments

  • irled.png
    3 KB · Views: 1,249
Re: Typical IR LED; what is the voltage drop & max curre

William At MyBlueRoom said:
Seems I'm looking in the wrong place on Google for IR LED datasheets. I do recall they can be used at upto 100ma (50% duty cycle?) are they 1.2v drop? 1.7v?
Click to expand...

You need to look for the specific one you have, try LD274 for one I happen to be using at the moment. I'm running it off 3V (2xAA) from a 16LF628, using an NPN driver with a 6.8 ohm series resistor.

It's normal to pulse tham around 1A, with a fairly low duty cycle.
 
Thanks Nigel, your experience is helpful as always. Perhaps you could clarify the following spec in the datasheet. Since I'm using 5v does it mean the diode will drop 1.9v
 

Attachments

  • ld274vf.png
    4.3 KB · Views: 919
William At MyBlueRoom said:
Thanks Nigel, your experience is helpful as always. Perhaps you could clarify the following spec in the datasheet. Since I'm using 5v does it mean the diode will drop 1.9v
Click to expand...

Looks like it to me!.
 
The voltage across the LED will be 1.9V with a forward current of 1A. And note the 100 us pulse requirement, ie. the 1A must not be on for longer than 100 us.

With a current of 100 mA it will be 1.3V, note the 20 ms pulse.

Given the brief extract quoted, these appear to be typical figures. The maximums are 1.5 V and 2.5V respectively.
 
I mean tp/T. Typically what should I set in 100mA 20ms, or 200mA ~10ms, or 1A 100us?
In 20ms 50% or 20%?
Or in for example 500mA ?
 
Last edited:
togi88 said:
I mean tp/T. Typically what should I set in 100mA 20ms, or 200mA ~10ms, or 1A 100us?
In 20ms 50% or 20%?
Or in for example 500mA ?
Click to expand...
Again, you do not talk in English.
What do the 3 letters tp/T mean in English words?

Oh, I think you are asking what pulse width for certain LED currents?
The datasheet should say. The example that was posted shows a max of 100mA for 20ms or 1A for 100us.
 
Yes, my english is not the best . I am interested by the pulse width, I[A] and the lighting time (perhaps a typical caracteristics with different pulse width curves). I have some 5mm IR LED at home, they are different types and I dont know the exact type. That's why I ask the typical datas of an IR led.
 
We do not know the spec's for your IR LEDs.
Buy new LEDs that come with important datasheets.
 
Status
Not open for further replies.

Similar threads

  • Question
What is the maximum temperature of a lithium battery when overloaded?
Replies
4
Views
670
rjenkinsgb
  • Question
What is the waveform and frequency of the lcr t4 device when testing the capacitor?
Replies
7
Views
676
danadak
Y
  • Question
What is this?
Replies
4
Views
782
Tony Stewart
D
What value is this melf faceless diode?
Replies
8
Views
1K
dalbo
D
J
what is the blue in the photo
Replies
16
Views
2K
jazjaz
J
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…