[Laser] led txr

[I]

Hello again folks,


Lets just say then that here is a working practical design for a transverter and LED transceiver using a modern high power LED and leave it at that.
I think Edison and Swan had the same problem with the light bulb! I am not really concerned about that issue, rather, I am more keen to share my stuff with all you who are interested.
I think most of us already knew LEDs would detect light, and Tim told me he remembered some short range stuff from a while ago.
It was also very interesting to hear of all the historic stuff, particularly with various crystals though.


Now for some practical help with the microsurgery. I do not have a good enough image, but there is some help here, if you  have got the correct LED W5SM HYJY-1-Z, (who knows, others may work as well), this is available from RS components in Europe, part number 665-6189.
They have a datasheet http://docs-europe.origin.electrocomponents.com/webdocs/0d15/0900766b80d159a7.pdf which has a drawing towards the end of the document. It shows the internal lozenge shaped terminal above the cathode connection. There is one gold wire that goes from this terminal to the LED chip in the middle, and another that goes from the terminal to the protection diode at the left (at eight o'clock if it were a clock face) just use a sharp knife and press down on this wire, its only silicon gell. As I said your multimeter will show 1.056V forward volts until you break the wire when it will show open circuit. A friend who has tried it, and I have not wrecked an LED yet. I have tried voltages up to 50V in reverse, but using a 100k resistor in series (as per the circuit), up to a certain voltage you get a signal, beyond that you hear the noise increase. It is just a matter of finding the optimum which has varied for me from 43V up to nearly 48V. Please remember to use at least a 63V rated capacitor in the circuit to decouple the reverse bias supply to the LED ( and do not forget the 33 ohm resistor in series or you will weld the relay contacts). Someone forgot about the voltage rating an used a 25V capacitor and found 200microamps of leakage which pulled the reverse bias down to 30V. The resistance is so high that I have not managed to destroy an LED yet. The original link details experiments up to over 200V.


I hope I have covered all the questions,






Stuart G8CYW