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ralphjy

Laser Operating Sign

Posted by ralphjy Top Member Jan 18, 2020
I'm continuing to work on enhancing my laser setup.  One item on the list is a warning indicator that the laser is operating and that it is not safe to enter the room.  I plan to put it outside the door to my computer room (the access to the workroom with the laser is through the computer room), so one requirement is that the indicator should be remotely controlled via WiFi or Bluetooth.  I received an Adafruit 8266 Huzzah board in the latest Element14 goodie bag and that seemed l ...
Introduction   Having used JFETs (type BF256B) in some of my test circuits whilst experimenting with MOSFETs, I thought it might be interesting to look at the transfer function and see if I could recreate the curve you sometimes see on a datasheet which relates the gate voltage to the drain current.   If you're not used to JFETs (Junction Field-Effect Transistors), they're similar to MOSFETs but the insulation between the gate and the channel is provided not by an actual insula ...
ralphjy

Trying out my laser

Posted by ralphjy Top Member Jan 7, 2020
Santa brought me a laser for Christmas and I finally picked up the last piece of required safety equipment - a CO2 fire extinguisher.  So, I finally get to give it a try .   I have a SainSmart Genmitsu 3018 Pro CNC router that has provisions to swap the spindle for a laser module.  I am using a SainSmart 445nm 5.5W laser kit.  There are less expensive modules available, but I've found that it is difficult to get a good set of specifications on these units and decided it wa ...
Introduction   More experimenting with MOSFETs. This time I'm going to have a look at the output characteristics.   On a datasheet, output characteristics are usually drawn something like the following two graphs. The first is for the IRF730 part that I have been experimenting with extensively in this series of blogs and the second is for a small-signal part, a BS170:   Curves of drain current against drain-source voltage are drawn for a set of fixed Vgs voltages. The Vgs ...

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