Re: Bleeder resistor for power supply size?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, JanRwl@A... wrote:

> In a message dated 7/6/2003 8:29:43 PM Central Standard Time,
> davemucha@j... writes:
>
> > Is there some pressing reason to drain the power ?
> >
> Dave and others on this thread: If the dozens who might "build

something",

> yet without a CLUE what electrons look like, are ALL very careful

not to TOUCH

> anything, then NO bleed, or let the LOAD perform that task is

fine. HOWEVER,

> if any of this same group of "dozens" ever do their own checkout,

repair, s

> howing-off, or "adding in something else not yet thunk of", they

can get a

> SURPRISE with even only 30 volts stored in a 15,000 µf and larger

cap! It will RUIN

> the tips of some nice tools, and leave "nasties" on otherwise

brite, shiny

> terminals or tops of transistors,etc.!
>
> Another "bleed" that is NO big deal, AND, will "show" what's going

on, is

> simply a good brite LED with the approp. resistor (figure it to

permit 15-20 mA

> to flow through the LED when power's on). This can REMIND you not

to go pokin'

> your shiny new tools about between terminals, and how long it will

be before

> the "dangerous juice" is sufficiently dissipated! It further acts

as your

> "Main DC" pilot-lamp! GOTTA have one of those anyway!
>
> Jan Rowland
>
>
> [Non-text portions of this message have been removed]

Sure, an LED on the cap is a standard device to let one know that
power is on. seems that a simple shorting block would be common
sense whenever one works around a cap. I use a Craftsman #2 Phillips
shoring bar before I ever touch a cap...well, usually. Even if it
has been on the shelf for a few years.

Been there, done that. Just checked, the scar from the photo flash
has healed completely. lemme see that was in March I think. Got too
excited while driving and wanted to see what was inside those
disposable cameras. Seems a flash discharge does not drain them
completely.

And you are correct, had that be my 68,000uF cap on the power supply,
I probably would not be writing this. : )

Dave