Pulsing a 2W Laser Diode w/ 26 AWG Wire - Is Gauge Okay?

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Discussion Overview

The discussion centers around the suitability of using 26 AWG wire for pulsing a 2 Watt laser diode at frequencies of 1-10 MHz. Participants explore concerns related to wire gauge, current draw, heat dissipation, and transmission line effects in the context of a short wire length.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant, roeb, questions whether 26 AWG wire is appropriate for pulsing a laser diode at around 1-2 amps, noting that the maximum free-air amperage is 2.2 A.
  • Another participant suggests considering twisted pair (TP) cable, such as CAT-5 or CAT-6, which is 24 AWG and readily available.
  • roeb mentions the wire length is less than 10 cm and expresses uncertainty about the power going through the wire in relation to the BNC connector size.
  • A later reply indicates that while AWG 26 may not be a problem, transmission line considerations might be important depending on the application.
  • Questions are raised about the use of a 50 Ohm coax cable and how the connections to the BNC and diode are made, including whether a ground plane is utilized.

Areas of Agreement / Disagreement

Participants express differing views on the appropriateness of 26 AWG wire, with some suggesting alternatives and others raising concerns about transmission line effects. The discussion remains unresolved regarding the best approach.

Contextual Notes

Participants have not reached a consensus on the suitability of the wire gauge or the implications of transmission line effects. There are also uncertainties regarding the actual current draw and the specifics of the connections being used.

roeb
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I am going to be pulsing a laser diode at around 2 Watt (room temperature) with a frequency of around 1-10 MHz. Right now I'm planning on using 26 AWG wire. Anyone have any thoughts on whether this is okay? Is the gauge okay? Since it's pulsed I assume I don't have to worry as much about heat dissipation..

I'm not sure of the actual current draw but it should be around 1 - 2 amps.
According to this website http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity
the max free-air amperage is 2.2 A. I'm kind of skirting the boundary there...

Thanks,
roeb
 
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roeb said:
I am going to be pulsing a laser diode at around 2 Watt (room temperature) with a frequency of around 1-10 MHz. Right now I'm planning on using 26 AWG wire. Anyone have any thoughts on whether this is okay? Is the gauge okay? Since it's pulsed I assume I don't have to worry as much about heat dissipation..

I'm not sure of the actual current draw but it should be around 1 - 2 amps.
According to this website http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity
the max free-air amperage is 2.2 A. I'm kind of skirting the boundary there...

Thanks,
roeb

Why are you using 26AWG? How long is this cable? Since you should use twisted pair (TP) cable, why not use a piece of CAT-5 or CAT-6 TP? That's 24AWG, and easy to come by...
 
Hey, I guess I'm not using that stuff because I'm kind of short on supplies.

So the length of wire itself is less than 10 cm. I'm just soldering a BNC connector to a veroboard and using the AWG 26 wire to connect to diode. The signal pin of the BNC connector itself doesn't look all that much larger than the wire I'm using, but I'm not quite sure if I need to worry about the power that's going through the wire.
 
roeb said:
Hey, I guess I'm not using that stuff because I'm kind of short on supplies.

So the length of wire itself is less than 10 cm. I'm just soldering a BNC connector to a veroboard and using the AWG 26 wire to connect to diode. The signal pin of the BNC connector itself doesn't look all that much larger than the wire I'm using, but I'm not quite sure if I need to worry about the power that's going through the wire.

I don't think the AWG is a problem. But depending on the application, you may need to be careful about transmission line considerations. Do you have a 50 Ohm coax cable coming from somewhere that connects to the BNC connector on your board? Are you using TP to connect the center conductor and ground ring of the BNC to your diode's connections? Or are you using a ground plane on your board to route the ground of the BNC to the - terminal of the laser diode?