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From: Phil Hobbs on 15 Jun 2010 17:38
Grant wrote:
> On Tue, 15 Jun 2010 10:28:50 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote:
>
>> On Tue, 15 Jun 2010 11:58:41 -0500, "amdx" <amdx(a)knology.net> wrote:
>>
>>> "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in
>>> message news:3iaf169d6vhlk2u4ot1g9da5indnv2ng9f(a)4ax.com...
>>>> On Tue, 15 Jun 2010 10:57:35 -0500, "amdx" <amdx(a)knology.net> wrote:
>>>>
>>>>> like I said before, I have always
>>>>>>> enjoyed your input here and hope to continue enjoying your humor and
>>>>>>> gaining from your knowledge.
>>>>>> So post a circuit so I can "critically" analyze it :-)
>>>>>>
>>>>> Ok Jim,
>>>>> I'll subject myself to critical analyses of a very simple circuit I used
>>>>> in a retrofit
>>>>> about 15 years ago. It is a debounce circuit using parts at hand done in a
>>>>> way
>>>>> I never saw before. It worked great in my situation, but I don't know if
>>>>> it
>>>>> had
>>>>> any wider application.
>>>>> Because I was curious, I did attempt to have this analyzed on this group
>>>>> many years ago. No one took me up, maybe it was so bad they didn't want
>>>>> touch it.
>>>>> Now be nice, (if you can :-) I have no formal electronics education and
>>>>> my
>>>>> only claim to fame is as a tech repairing 11,000 VCRs in 10 years.
>>>>> That started 25 yrs ago and ended was 15 yrs ago. VCRs got so cheap to
>>>>> repair, I had to stop.
>>>>> I posted my debounce circuit at,
>>>>> http://i395.photobucket.com/albums/pp37/Qmavam/Debouncejpg.jpg
>>>>> Mike
>>>> No problem with that circuit as long as you gave yourself adequate
>>>> margin on holding current that a second rendition will work without
>>>> changing resistor values... I'm seriously restrained by repeated
>>>> manufacturability, so I'm overly cautious.
>>>>
>>>> Cheaper? Use a PNP/NPN, then you could have resistor values determine
>>>> holding current.
>>>>
>>> Well that wasn't much fun !
>>> Re the PNP/NPN, I used the SCR spec that once turned on
>>> it stays on until current falls below a minimum, eliminateing switch bounce.
>> "Minimum" must be less than "holding current"... look at an SCR data
>> sheet.
>>
>>>>> PS. When you get this fixed I have a unique power supply circuit I want
>>>>> you to finish, it will be simple for you. I'll search my computer and see
>>>>> if
>>>>> I can find it, I started that about 12 years ago.
>>>>>
>>>>>
>>>> Next :-)
>>>>
>>>> ...Jim Thompson
>>> I have searched 3 HDs and didn't find the power supply, I'll keep looking.
>>> Here is a scope probe mod I needed while measuring up to 700v with a scope
>>> spec for 400V. Note; values may need adjust for your scope and probe.
>>> http://i395.photobucket.com/albums/pp37/Qmavam/X20Scopeprobeadapterjpg.jpg
>>>
>> Myself, I bought a TEK HV probe/isolator, so I could probe off-line
>> without risk of electrocution.
>>
>> I also had the GenRad electricians install "panic" button switches
>> around my lab, plus a rule: no working alone.
>>
>> Slam a panic button, and the whole place went off-line, except the
>> ceiling lighting.
>
> Did you ever need to hit one of those panic buttons?
>
> Stuff I'm working on at the moment powered by 24V from a couple sets of
> SLA batteries (big ones are 100AH), so I'm more worried about fire than
> high voltage these days. Individually fused batteries and quality
> connectors to limit fault current.
>
> Grant.

They have to be tested every year. At my PPOE we used to hit the EPO
button on the way out for the Labor Day weekend, when the place shut
down for Provocative Maintenance. (It always took a couple of days to
get everything working again when power came back up.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net
From: Jim Thompson on 15 Jun 2010 17:45
On Wed, 16 Jun 2010 07:31:12 +1000, Grant <omg(a)grrr.id.au> wrote:

>On Tue, 15 Jun 2010 10:28:50 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote:
>
[snip]
>>
>>Myself, I bought a TEK HV probe/isolator, so I could probe off-line
>>without risk of electrocution.
>>
>>I also had the GenRad electricians install "panic" button switches
>>around my lab, plus a rule: no working alone.
>>
>>Slam a panic button, and the whole place went off-line, except the
>>ceiling lighting.
>
>Did you ever need to hit one of those panic buttons?

Nope. Just periodic test.

>
>Stuff I'm working on at the moment powered by 24V from a couple sets of
>SLA batteries (big ones are 100AH), so I'm more worried about fire than
>high voltage these days. Individually fused batteries and quality
>connectors to limit fault current.
>
>Grant.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

The only thing bipartisan in this country is hypocrisy
From: kelly on 15 Jun 2010 21:28

"Jeroen Belleman" <jeroen(a)nospam.please> wrote in message
news:hv854s$t26$1(a)speranza.aioe.org...
> amdx wrote:
>> "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote
>> in message news:i63f16ptsg4a3opttkc6diasl2jt3m4ssf(a)4ax.com...
>>> [insults]
>>> ...Jim Thompson
>>
>> I haven't noticed anyone else jumping on John.
> > [...]
>
> I, for one, would much regret it if these fools ended up pissing
> JL off to the point of disappearing from the group. His contributions
> are more interesting than most.
>
> The trouble with this medium is that people can insult each other
> with little risk. The mark of a civilized man is that he stays
> polite even if no one can hit him.
>
> Jeroen Belleman

Yeah, I tend to agree. I've been around here for a decade+. I've noticed JT
going AWOL in the last year or two as well.


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