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Capacitors, info and a question please :)

S

Seany

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Ok so i've looked around a bit and my main question is about the DDL driver, or rather just the cap. I've seen so many different ones so i'm wondering, how much does it matter about the voltage and the uf rating.

From what i gather the voltage is what the cap will charge to (What happens if overloaded?) but i don't quite understand how the uf rating works.

Also when building a curcuit and testing i've read to short out the cap before you attach a diode but I don't know how to do this, Is it just putting a piece of wire across the pins?

Thanks in advance. First laser build coming soon :D :p

-Sean
 





The uF rating is the capacitance of the capaitor... it is what will help
eliminate spikes that could damage your Laser Diode..
Use the value stated on the DDL schematic..

The voltage rating of the capacitor should be at least two times higher
that the voltage that the capacitor will see in the circuit at any time...

Applying mor voltage than the rating of the capacitor will damage the
capacitor...:cool:

Jerry
 
Thanks Jerry, but about shorting it, is it that simple as to join the pins together?

Also i'm interested in seeing this esplosive property you speak of photon. Any youtube vids? (I've seen many start fizzing and look like they'll pop but that's heat related.)

-Sean
 
Just place a 100 ohm resistor over the pins, it will bleed the cap out slow.

You can just short the pins, but be ready sometimes they throw a fat spark that way.

to blow one up, just take a sacrificial capacitor and push too much voltage to it.

That "X" mark on the top is for pressure relief when the electrolyte inside starts boiling.

I have been around electronics since the 1970's so I think I have seen every failure that can happen.
 
Well i'll be using the same as described in the DDL curcuit page so 16V, i don't imagine they could put out much of a spark lol. Is there a way to make some sort of "bleed switch" into the DDL curcuit so you can flip that and it'll drain it...Think i'll have a little mess around with some resistors and a little bit of extra curcuit. You gave me an idea photon :) thanks

-Sean
 
Actually, a 1,500 Ohm bleeder resistor will be OK. It will discharge the cap in about one second. a 1/4 watt resistor will be fine up to 5 volts. A smaller bleeder resistor will be good at 3 volts. Do the math.
I've been preaching Bleeder resistors for years.

HMike
 
Good call Mike...
as to the Meatball video... what a waste of time...:undecided:
It's like looking at some Dork pumping 220 Volts into his Iphone...
what's the point...:thinking:

Jerry
 
Sorry Lasersbee... I saw it the other day, and this thread reminded me of it. I didn't think leds could be so violent... even at HV.
 
Any (or most) low voltage device exibit a highly violent aftetmath subjected
to extreme high voltages...

Jerry
 
photonaholic said:
Ever see one blow the can off??
Click to expand...

i have. it actually was rated for around 15V but i put 25V through it... it shot off the metal can across the room. it sounded like a gunshot too.. when i looked at the can it blew off there was a hole in the top

pretty sweet but pretty scary when you're not expecting it. same with touching + and - on 120V after putting solder on them. its the bright flash you'll ever see. and the solder will pretty much vaporize n send melted solder flying everywhere
 
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