Driver to drive?

Nico Coesel · Nov 28, 2004

Guy Macon <http://www.guymacon.com> wrote:

One of the fellows working for me designed this:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3856393230

It's a simple product, but any comments on the design of it
would be most appreciated.

Looks neat. But why screw-terminals? I would prefer the speaker like
terminals. No tools needed. Or even better: 4mm jacks with screw
posts. So you can connect loose wires or standard test leads without
tools.

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl

CJT · Nov 28, 2004

Guy Macon wrote:

One of the fellows working for me designed this:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3856393230

It's a simple product, but any comments on the design of it
would be most appreciated.

I think it's a safety hazard, with all that exposed wiring.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form che...@prodigy.net.

Guy Macon · Nov 28, 2004

classd101 wrote:

I just spend a few evennings researching 3.5" HDDs before ordering a
replacement. I think the smallest I've seen most manufacturers still
making is 20GB.

Several manufacturers still make 8.4GB drives, and they sell fairly
well - that's the biggest drive many older systems can handle.

Guy Macon · Nov 28, 2004

Nico Coesel wrote:

Looks neat. But why screw-terminals? I would prefer the speaker like
terminals. No tools needed. Or even better: 4mm jacks with screw
posts. So you can connect loose wires or standard test leads without
tools.

Good idea. Do you have a part number that you like (and won't cost
an arm and a leg)? We only made 100 of them, and doing a re-layout
isn't a problem.

Fred Bloggs · Nov 28, 2004

Guy Macon wrote:

One of the fellows working for me designed this:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3856393230

It's a simple product, but any comments on the design of it
would be most appreciated.

What is it used for? Didn't PC SPICE kill the market for these things?

Bill Sloman · Nov 28, 2004

Mike Diack <moby@kcbbs.gen.middleearth> wrote in message news:<Xns95AFBD93F8587mobykcbbsgennz@203.96.92.12>...

bill.sloman@ieee.org (Bill Sloman) wrote in
news:7c584d27.0411271516.5d8dab21@posting.google.com:

Some humans.

As Fred Bloggs has pointed out, some African Grey parrots seem to be
able to outperform ostensibly human posters on this user-group.

------
Bill Sloman, Nijmegen

That's all very well, but how many newsgroup inhabitants could you say have
"lovely plumage" ?

Until web-cams get a lot more popular, and this usergroup gets more
tolerant of the rather large binary files involved in transfering
images, we can't say anything about the plumage of its inhabitants.

----------
Bill Sloman, Nijmegen

John Fields · Nov 28, 2004

On Sun, 28 Nov 2004 13:44:04 +0000, Guy Macon
<http://www.guymacon.com> wrote:

One of the fellows working for me designed this:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3856393230

It's a simple product, but any comments on the design of it
would be most appreciated.

---
Junk.

--
John Fields

NSM · Nov 28, 2004

"Guy Macon" <http://www.guymacon.com> wrote in message
news:10qjlhl62bs6o98@corp.supernews.com...
|
| One of the fellows working for me designed this:
|
| http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3856393230
|
| It's a simple product, but any comments on the design of it
| would be most appreciated.

The more things you combine into one box the worse it is. KISS.
I prefer two clip leads and a selection of parts.

YMMV.

N

Nico Coesel · Nov 28, 2004

Guy Macon <http://www.guymacon.com> wrote:

Nico Coesel wrote:

Looks neat. But why screw-terminals? I would prefer the speaker like
terminals. No tools needed. Or even better: 4mm jacks with screw
posts. So you can connect loose wires or standard test leads without
tools.

Good idea. Do you have a part number that you like (and won't cost
an arm and a leg)? We only made 100 of them, and doing a re-layout
isn't a problem.

Farnell 143-550 looks nice. Around EUR 1.15 if you buy 100.

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl

Winfield Hill · Nov 28, 2004

BFoelsch wrote...

Try vodka and Milk of Magnesia some time.

I think that's called a Phillip's Screwdriver...................

................... rimshot!

Hkmm, does that also need OJ in it?

I did come across this,

Phillip's Head Screwdriver
- 3 oz Vodka
- 3 1/2 oz Orange Juice
- 3 1/2 oz Milk

If mixed wrong it tastes like curdled milk, if mixed right it
tastes like a creamsicle with Vodka.

--
Thanks,
- Win

Blake · Nov 28, 2004

. . . but any comments on the design of it
would be most appreciated.

DIP switches are fine for use in set-and-forget applications, but as
controls on a piece of test equipment? I doubt they will hold up very long
in daily use.

Jim Thompson · Nov 28, 2004

On Sun, 28 Nov 2004 20:19:09 GMT, nico@puntnl.niks (Nico Coesel)
wrote:

[snip]

BTW, over here I can buy an HP2500L Color Laserjet for 417 Euro's
(aprox. $US 500) including VAT.

That's the one my printer repairman DOESN'T recommend, on durability
grounds. (But then he regularly takes them apart

480)460-2350 | |
| E-mail Address at Website Fax

Nico Coesel · Nov 28, 2004

Jim Thompson <thegreatone@example.com> wrote:

On Sun, 28 Nov 2004 20:19:09 GMT, nico@puntnl.niks (Nico Coesel)
wrote:

[snip]

BTW, over here I can buy an HP2500L Color Laserjet for 417 Euro's
(aprox. $US 500) including VAT.

That's the one my printer repairman DOESN'T recommend, on durability
grounds. (But then he regularly takes them apart

It depends on how much you're planning to use a printer. You can't
expect a cheaper model to last long if you are going to print 24/7.

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl

CBarn24050 · Nov 28, 2004

Subject: What do you think of this design?
From: Guy Macon http://www.guymacon.com
Date: 28/11/2004 13:44 GMT Standard Time
Message-id: <10qjlhl62bs6o98@corp.supernews.com

One of the fellows working for me designed this:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3856393230

It's a simple product, but any comments on the design of it
would be most appreciated.

Practicaly useless, no good as an accurate cap box as there is too much
unpredictable stray cap. No good at anything over video frquency due to self
resonance. Will emit and pickup all manner of emi. If that wasn't enough this
is a product that is allready in the marketplace for decades, invent something
new!

Active8 · Nov 28, 2004

On Sun, 28 Nov 2004 12:33:30 -0800, Scott Miller wrote:

I don't know how tight your voltage spec is, but would a separate
sense winding do it?

--
Best Regards,
Mike

Joerg · Nov 28, 2004

Hi Scott,

This is frequently done with a Texas TLV431 or similar from other
sources such as National. Cheap, small, available at almost every street
corner but best of all, well under a uA on the ref pin. You wouldn't
really need the ADC here.

As for resistors, it is customary to connect some in series in HV
applications. It would be hard to obtain anything below 5% when you are
above the 10M region.

Regards, Joerg

http://www.analogconsultants.com

Pooh Bear · Nov 28, 2004

Scott Miller wrote:

I got bored yesterday and started working again on a Geiger counter design I
came up with a couple of years ago. The high voltage power supply was
mostly cribbed from a couple of other designs I found, since I'm a digital
guy and high voltage isn't my thing. As it stands now, the microcontroller
puts out a square wave that drives the primary of a transformer via a
MOSFET. A voltage doubler on the secondary gets the voltage into the
required range (500+ volts in this case), and a couple of varistors in
series form a shunt regulator.

It's the shunt regulator I'm looking to replace right now. Since the input
to the inverter is provided by the MCU's timer channel, it can be easily
pulse-width modulated. I just need to get some feedback from the HV side so
the MCU knows how to adjust the duty cycle. My first thought was to use a
pair of resistors to form a voltage divider and feed maybe 1/120 of the
output voltage into the MCU's A/D converter. But with any reasonable
resistor values, there's too much load on the supply to maintain the needed
voltage. Higher values might work, but the thick film resistors are
expensive and I'm not sure how much current the ADC needs to function
correctly.

Any suggestions? I'm thinking an op amp might help, with its high input
impedance. That still means using expensive thick film resistors, though.
And again, I'm a digital guy and I'm a bit out of my element here.

I'm really trying to keep the cost and component count down to make it an
easy hobby project, but I'd also like it to not suck a battery dry in 2
hours. If anyone's got any suggestions on how to implement a better
regulator, or maybe a different supply design entirely, let me know.

Current schematic is at: http://n1vg.net/geiger/images/gc1-9v.png. The HV
supply is on the right-hand side - everything from MCU pin 13 to the
Geiger-Mueller tube. The pin header at left is for an LCD display.

Any PSU using a *shunt* regulator is hopelessly inefficent.

What regulated voltage do you need ?

Using 'spare cycles' on an MCU is a truly lousy way to do it btw. Far better a
dedicated controller chip.

Graham

Jonathan Kirwan · Nov 28, 2004

On Sun, 28 Nov 2004 12:33:30 -0800, "Scott Miller" <scott@3xf.com> wrote:

I got bored yesterday and started working again on a Geiger counter design I
came up with a couple of years ago. The high voltage power supply was
mostly cribbed from a couple of other designs I found, since I'm a digital
guy and high voltage isn't my thing. As it stands now, the microcontroller
puts out a square wave that drives the primary of a transformer via a
MOSFET. A voltage doubler on the secondary gets the voltage into the
required range (500+ volts in this case), and a couple of varistors in
series form a shunt regulator.

On a Geiger counter I built many years ago from scratch, I used the recommended
idea of a string of series NE-2s. Worked great. I still have that Geiger
counter and, aside from replacing the tube once, it's still working just fine!

Jon

Scott Miller · Nov 28, 2004

I'm really not sure. There's still a doubler after the secondary winding
that's going to introduce some loss. The bigger problem is finding the
right transformer. Winding a custom one isn't an option. I'm currently
using a $3 CCFL driver transformer - it's compact and works pretty well.

Scott

"Active8" <reply2group@ndbbm.net> wrote in message
news:15fl80d6krh4k.dlg@news.individual.net...

On Sun, 28 Nov 2004 12:33:30 -0800, Scott Miller wrote:

I don't know how tight your voltage spec is, but would a separate
sense winding do it?

--
Best Regards,
Mike

Scott Miller · Nov 28, 2004

How would you set one of these up in a high voltage circuit? And wouldn't
any shunt regulator still be pretty inefficient?

Scott

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:mFrqd.51217$QJ3.2808@newssvr21.news.prodigy.com...

Hi Scott,

This is frequently done with a Texas TLV431 or similar from other sources
such as National. Cheap, small, available at almost every street corner
but best of all, well under a uA on the ref pin. You wouldn't really need
the ADC here.

As for resistors, it is customary to connect some in series in HV
applications. It would be hard to obtain anything below 5% when you are
above the 10M region.

Regards, Joerg

http://www.analogconsultants.com

Driver to drive?

Nico Coesel

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CJT

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Guy Macon

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Guy Macon

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Fred Bloggs

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Bill Sloman

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John Fields

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NSM

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Nico Coesel

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Winfield Hill

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Blake

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Jim Thompson

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Nico Coesel

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CBarn24050

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Active8

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Joerg

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Pooh Bear

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Jonathan Kirwan

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Scott Miller

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