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FrozenGate by Avery

Beginner Help






MF or MFD is another way of saying µF. So that's 2200 vs 16. I won't say it won't work because it is just a filter capacitor, but it would be unusual and not what's written.

About the placement of the filter cap... when placing a cap next to a diode you have to be careful that the capacitor is fully discharged before hooking up the diode, otherwise the spike from the cap will destroy the diode. In my own designs I place the filter cap before the regulator, to avoid this issue. There shouldn't be any apreciable ripple from a LM317 in current regulation mode, but there could be a lot of ripple from whatever you're powering it with. I also use 47µF caps for filtering.
 
what do you mean with discharged? holding the top of the scewdriver at the 2 thingys?
 
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Yeah, shorting it out (connecting the two terminals) with a screwdriver works, that's a good way of doing it.

Capacitors can hold charges near indefinitely, so if for some reason they should be even partically charged, be it static electricity or from an old power source, it can cause a lot of damage. It is good practice to always make sure a capacitor is discharged before installation.

Also, know that with a capacitor next to your laser diode, if for any reason the capacitor or the diode should become disconnected, even for a fraction of a second while the power is on, or recently on, it can kill your diode with a spike. That's another reason I don't use filter caps on the output of linear regulation drivers. Having a cap on the input should be enough.
 
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