Electronics without adult supervision

[Bradfo69]

OK.... I admit it. I have no business being on this forum or attempting to build/fix anything.

Give me house current... you know, "electricity that requires a real size screwdriver". I'll take that all day long. This "electronics...microscopic... 3 volt -5 volt" shit, just kicks my ass.

I "think" I fried a $130 blue ray diode from DTR within a couple seconds yesterday. It never actually got very bright and I think it was only around 3-4 volts and the current knob on the power supply wasn't really turned up. And then all of a sudden it just stopped glowing. I had it focused but, I can honestly say that for something that should do 300-500mW, it hadn't even gotten as bright as a 5mW penlight 405nm I have. It occurred to me that perhaps I don't really know how to use a power supply properly or, this Mastek style $70 ebay benchtop supply of mine is a piece of crap...

Regardless... is there a good "diodes for dummies" video or thread somewhere? Or maybe a recommended Electronics 101 book? Of course, if I "don't" figure this crap out, there could be a whole lot of lenses, holders, drivers, diodes, and other stuff hitting the buy/sell thread... 'cause I'm a touch bit frustrated.

[VDX]

... I'm driving my diodes with current regulators, built with LM317 (for currents from 50mA up to 1Amp) or LM338 (up to 3Amps) and a resistor, defining the current.

Continuous running BluRay-LD's or the 445nm-LD's with some hundred Milliamperes or high-power IR-LD's with currents up to 9Amps with more of the LM's in parallel.

The only occasions, where a diode was blown, it was for not proper cooling (e.g. testing without inserting in a cooler or clamping to a thermal sink).

But when driving the diodes with a voltage regulator you have to be really cautious about voltage spikes when switching the PS on or off ... as this is much more the 'killer' for LD's ...

Viktor

[Bradfo69]

I don't think this was heat as the diode was only glowing between about 5-10 seconds and it was in copper, in a Aixiz holder, with a driver set to 350mA and leads attached. Should have been "plug and play". All I did was apply power from a benchtop power supply at below lasing threshold and increased it slightly. I checked the supply with a meter ahead of time and know it was below 5 volts DC.

[-bart-]

12 ways to kill a diode (in no particular order)

• ESD
• Reversed polarity
• Over-voltage surges caused by bad or intermittent contacts driver<->diode
• Over-voltage surges caused by bad brownout behavior of driver (bad driver design)
• Over-voltage surges caused by adjusting pots 'live' (bad driver design)
• Over-current/voltage caused by surges in supply voltage (bad driver design)
• Over-current causing failure of diebonds.
• Over-heating caused by thermal runaway
• Over-heating caused by insufficient cooling
• Back reflection
• COD
• Any dust or deposit on the die-facet (open cans)

[norty303]

I'm just trying to figure out what is connected to what here.
So the bench supply was connected to the modulation lines?
What was driving the actual driver, and at what V and current?

[Bradfo69]

You forgot #13

- Numpty at the helm.

[norty303]

Also, had you set up the driver current for the required output with 5V mod? If so, what had you set it to?
Is the diode case +ve or -ve?

[Bradfo69]

I'm just trying to figure out what is connected to what here.
So the bench supply was connected to the modulation lines?
What was driving the actual driver, and at what V and current?

O.k - bottom right assembly, set by DTR to 350mA. https://sites.google.com/site/dtrlpf...12x-405-diodes

Then, this power supply:



Red lead from power supply to red wire on the module, black lead from supply to black wire on the module.

Started with current and voltage turned all the way down. Then turned up the voltage a little and watched the display go up to between 3-4 volts. The diode glowed a little, turned up the current knob just a little and increased the brightness. Turned the focus ring just a little to get it from a pencil eraser size spot down to a tighter dot and within a couple seconds, it just went dark. It wasn't particularly bright - as I said, nowhere near as bright as my pen style 405nm 5mW (rumor) pointer that uses 2 AAA batteries.

Oh, and DTR said it runs between 3 and 5.5 volts.

[Bradfo69]

Also, had you set up the driver current for the required output with 5V mod? If so, what had you set it to?
Is the diode case +ve or -ve?

Not the faintest idea what you mean by "+ve or -ve".

[norty303]

Positive and negative