Re: [regenrx] Re: low voltage hybrid system
- Yeah Bill, I was just gonna say that.
One of the worst things to do is assume someone has turned off the power for
you. I was working on a gun director once and had assumed that the power was
off. I quickly learned otherwise when I cut through a 440V cable. The
lighting systems in most modern buildings is 277V. I got zapped on the head
once by a live cable dangling from the ceiling. I....What was I saying?
----- Original Message -----
From: "Bill Cromwell" <wrcromwell@...>
Sent: Sunday, April 28, 2013 9:22 AM
Subject: Re: [regenrx] Re: low voltage hybrid system
> On Sun, 2013-04-28 at 08:06 -1000, Leonard Meek wrote:
>> I'm a little curious. Has anyone ever been killed by 380 V in a radio
>> chassis? Or even an AC/DC radio? Aside from taking the radio into the
>> shower, I don't see the danger of working on high voltage power
>> supplies, as
>> long as they're unplugged first.
> Hi Leonard,
> The short answer is yes. It's less about the voltage and more about the
> current. Not forgetting of course that voltage forces that current.
> There are so many variables regarding path resistance in our bodies that
> change day to day and even hour to hour and consequences that vary
> according to the exact path taken. When I got across that 400 volt DC
> supply the current contracted all the right muscles to launch the power
> supply across the room (with no visitors). So I was spared. *THAT* got
> my attention and I have not been "poked" since. I can so easily remember
> all the way back to that time and will probably *never* forget. Some
> people haven't been so lucky.
> I have read that somewhere over about 20 volts 'can' kill. Those 12 volt
> DC automotive systems and batteries can severely injure you so please
> don't get sloppy careless working with "safe, low voltage" systems.
> There are people here and there walking around with missing body parts
> from getting across 12 volts DC! And That doesn't including battery
> explosions from dead shorts (shrapnel ya know).
> When you are working on exposed electrical gear remove *ALL* of your
> jewelery. Rings, watches, bracelets, ornaments in your piercing, - all
> of it. Yes..that big honking belt buckle too.Always check for the
> presence of voltages before touching anything. Connect clip-on meter and
> instrument probes with the power off. Always keep in mind that if you
> fumble something just let it drop. Don't lunge to grab it! Most of the
> safety "rules" are well published. Post them prominently in your work
> space and look at them every day.
> Bill KU8H
> "In the interest of Regenerating radio's lost art of Regeneration"Yahoo!
> Groups Links
I think that low voltage tube recievers :
1/ are interesting and use "new" constructions because circuit is other than HV tube receivers or transistor/IC receivers
2/ because we need not "new tubes", we have many and many old tubes (often "unused") for tests (in Czech republic)
3/ because it is also a way for children: no danger voltage! and here is BIG problem destroy tube if you use only low anode voltage
4/ because you can use "test board" too - for instance here:
(here is not problem with tubes and low voltage, but big problem with JFET, MOSFET...)
Best regards, Jara "Rat"