Problems with diode, What i did wrong?

[chipdouglas]

you also don't mention how you connect the power supply to the diode. did you just tap the lead to the diode pins? if so you probably killed it with a voltage spike. fyi, always solder your connections. everytime there is a loose connection it makes possible for a voltage spike.

michael

 

[eyeballpaul]

Most likely you diode was killed by transient current.

Is that because of lamps?

you also don't mention how you connect the power supply to the diode. did you just tap the lead to the diode pins? if so you probably killed it with a voltage spike. fyi, always solder your connections. everytime there is a loose connection it makes possible for a voltage spike.

michael

I soldered wires to diode pins, and shorted the circuit by simply sticking wires together. If that could cause voltage spike, should i turn on the PSU with already shorted circuit?

 

[youfellow]

It is possible. The incandescence bulb has the notorious characteristic that its resistance changes with temperature. When it was off, it has very low resistance, when it is lit, the temperature is 3000C, and resistance becomes the nominal value (as calculated from nominal power spec). To make it even worse, some bulb has the tungsten wire twisted like a spring, making it seemingly an inductor with large parasitic capacitance. I guess your bulb was not lit, but it may still have some effect.

Usually a good PSU has some kind of capacitor shunt to filtered out the on/off spikes. The filter of course is inside PSU. If you have some long wires, the spikes at the laser diode may not be filtered sufficiently by the filter inside the PSU. So always turn off the PSU first before you sticking/soldering the wires together/apart. Some bad soldering iron itself is not grounded and causes some spikes. Make sure you have a good soldering iron.

The laser diode can be destroyed in microseconds, and all precautions need to be observed. It's much less user-friendly than, for example, an LED.

Is that because of lamps?

I soldered wires to diode pins, and shorted the circuit by simply sticking wires together. If that could cause voltage spike, should i turn on the PSU with already shorted circuit?

 

[paoki]

Can a a-140 die by touching a solder tip on the end of 6cm wires attached on diode?
I hold it about 2-3 seconds, and felt the wires get hot. Don't have a driver to see whats going on.

 

[qumefox]

unless it was killed by ESD. No.

 

[paoki]

unless it was killed by ESD. No.

I have almost none equipment,i had a rkctr driver that i am not sure if it works, soldered wires from diode on to it, and on the other end i soldered two wires hooked to a cr2 and no light at all.

 

[pullbangdead]

A CR2 battery doesn't provide enough voltage to run a 445nm diode with a rkcstr driver.

 

[qumefox]

What's the driver current set at? Have you measured it on a test load? Checked your wiring and polarities? Made sure the battery wasn't dead?

You really need at least a DMM to do a DIY build and do it successfully.

 

[paoki]

What's the driver current set at? Have you measured it on a test load? Checked your wiring and polarities? Made sure the battery wasn't dead?

You really need at least a DMM to do a DIY build and do it successfully.

No clue about polarities. Driver is probably set around 200mA as it was attached to a phr.
I hooked it up to a square 9v battery, and wow blue light, it was very feint and weak though.

And, while everything seemed to go smooth, sparks start flying out of the driver, i tryed connecting again and the same happened, smoke out of the rkcstr.

Again I hope i haven't burnt my diode. I am waiting for a good tiped iron and a DMM to arrive.

 

[qumefox]

A few things. 200mA will kill a PHR pretty quick. Best not go more than 120mA with a phr.

200mA will also be BELOW the lasing threshold of a 1W casio diode. Generally they don't start lasing until around 225-250mA.

If you don't know anything about polarities, you should REALLY start reading everything you can about basic electronics, all the stickies here, etc. You'll just keep killing parts if you don't.

If your driver smoked, it's dead. Smoke from electronics is ALWAYS bad. Continuing to try to use it only risks your diode. Get a new driver. Learn how to wire it properly, build a test load, and set the current on the driver and make sure all is working properly before you hook it to your diode.

Also remember, it's usually a bad idea to run a driver with no load. It usually equals death on most of them. I know some will tolerate it, but it's good practice not to do it on any of them.

 

[paoki]

Thx man, from that i'l keep that my diode is probably still alive, as i read they are not as sensitive. But if something specific was ruined on the driver and current still managed to go to the diode it might have killed it.

Anyway im not touching it again till i get my equipment.

 

[eyeballpaul]

Ok, today i finally got my new psu with adjustable current, and decided to run a "LEDed" diode at different currents. Seems the diode obtained a strong resistance. It starts to emit dim light at ~200 ma, and becomes brighter till ~300 ma. Then PSU swiches to constant voltage mode. Is that an ordinary behaviour of a destroyed diode?

 

[qumefox]

What do you have the voltages set at?

CC-CV power supplies will only do CC up until they hit the voltage they're set at.

 

[eyeballpaul]

Voltage was set to 4.2v . But i just made another test, and i'm completely confused. When rising the voltage to 5v, current rapidly reaches 2A... Can't understand a thing.

 

[qumefox]

Sounds like the diode has something electrically wrong with it as well.

What kind of diode is it?

 

[eyeballpaul]

It's xj-A140 diode