Transmitter Circuit

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Moha998

Joined Mar 1, 2018
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WBahn

Joined Mar 31, 2012
25,249
And this is a digital design???

You can use any LED that reasonable meets the specs given. So go to DigiKey or Mouser and use their selection/search utilities to find reasonable alternatives. There will be no shortage of them.
 

Janis59

Joined Aug 21, 2017
1,057
RE:""I dont know how to calculate them""
Very easy, by means of Ohm`s law :)
First You do is set the led current. Voltage is Vcc-Vce-Vfd, where last two is 0,5...1 and 0,7...2,2 depending on datasheets. Vcc is Your battery voltage.
Then You divide this current by beta (sth around 100) and multiply with decent oversating factor, say 1,3...3, that will be Your base current.
Then calculate the base divider, thermal stability etc etc. There is one beautiful instrument for this aim, named AppCAD.
 

WBahn

Joined Mar 31, 2012
25,249
And this is a digital design???

You can use any LED that reasonable meets the specs given. So go to DigiKey or Mouser and use their selection/search utilities to find reasonable alternatives. There will be no shortage of them.
My apologies. I misread your post. I thought you were having problems finding the LED called for in a schematic.

After looking at the attached schematic, it appears to be coursework of some kind. Is it?
 

Dodgydave

Joined Jun 22, 2012
8,825
R3 needs to be lowered to 220 ohms,C1 will have an Xc from 8K to 72 ohms in your Frequency range.

Here is a better circuit. ..


IR_Circuit.jpg
 
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