very informative, thanks.
I look forward to the next two installments!
On Thursday, September 24, 2015 at 3:52:06 PM UTC-4, gregebert wrote:
>
> [Forking a new thread from the partially-lighted nixie]
>
> I've used 3 different linear (ie non-switching) HV supplies in my clock
> designs. I'll des
...And I thought optimizing a switching power supply was supposed to be
difficult!
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2. Instead of a voltage doubler, a 'boost' supply is another way to get
higher anode-supply voltage. One version (hvsupply.pdf) 'adds' a few volts
to the AC line before it's rectified, though it's not isolated. I use this
in my big clock to get around +220VDC. The other version
(neondr_pwrsupp.
Using a double primary as a substitute for a secondary is a big no-no! You
won't have the appropriate insulation to the mains. You will be just the
thickness of two layers of enamel from grabbing the mains supply if any
parts of the circuit can be touched. Scarry, isn't it?...
Compromizing safe
It's not the cost, but the availability. Ever since the demise of vacuum
tubes in the 1970's, high-ish voltage transformers have been getting
scarce. The only exception being transformers used in microwave ovens,
which produce way too much voltage. I'm leery of salvaged transformers
because the
I did some research on UL/CSA approved transformers, and there is a
requirement that all windings withstand a minimum breakdown voltage, even
if they are intended to be connected together, such as dual-primaries.
Depending upon the VA rating and the voltage, the breakdown must be between
1050 a
Can anyone direct me to a document that says that it is allowed to sell an
electronic apparatus that uses a primary winding as a secondary winding - I
spent a lot of time Googling this and I can't find anything. I am also
concerned about safety and what an insurance company would have to say if
If you are going to sell finished products, your best option is to use an
*external* agency-approved power-supply to produce ~12-18V. Laptop
computers are a good example of this practice. Of course, you'll need an
internal DC-DC converter so it's no longer a linear power supply :-(
Regulations
Having worked for UL as an engineer I have a few comments.
UL does not "approve" anything- they List, Recognize and Classify items.
"Approval" implies that an item can be used without regards to its limited
testing by UL. The UL lawyers hate the term "Approved By UL" and
routinely send out let
nixie
clock which is spread out on solderless boards. It uses 6 of the 8422
tubes and it uses 6 of the 74HC160 counters.
Chuck
>
>
> Original Message
>From: gregeb...@hotmail.com
>To: neonixie-l@googlegroups.com
>Subject: RE: [neonixie-l] Re: Linear power supplies for ni
as far as excessive current,
voltage,
power, and heat.
One of my rules of thumb: If it runs hot enough that I can't
hold my hand on it indefinitely, it's running too hot.
Chuck
Original Message
From: gregeb...@hotmail.com
To: neonixie-l@googlegroups.com
Subject: [neonixie-l]
you are correct. it is perfectly safe to use dual primaries (or
secondaries) for isolation. The wire is triple-coated with enamel,
plastic and another layer of enamel.
While I have a multi-thousand dollar Topaz 10kVA Ultra-isolator on my
development bench, we require something cheaper for produc
rom: Dekatron42
To: neonixie-l
Sent: Friday, October 02, 2015 4:37 PM
Subject: [neonixie-l] Re: Linear power supplies for nixies
Can anyone direct me to a document that says that it is allowed to sell an
electronic apparatus that uses a primary winding as a secondary winding - I
spent a lot
Reading your last post, I would suppose then,
that 5 volts would be considered "high tension" :)
>
>
> Original Message
>From: gregeb...@hotmail.com
>To: neonixie-l@googlegroups.com
>Subject: RE: [neonixie-l] Re: Linear power supplies for nixies
>
On 15-10-02 03:07 AM, Dekatron42 wrote:
Can anyone direct me to a document that says that it is allowed to sell
an electronic apparatus that uses a primary winding as a secondary
winding - I spent a lot of time Googling this and I can't find anything.
I am also concerned about safety and what an
On 10/02/2015 03:07 AM, Dekatron42 wrote:
> Can anyone direct me to a document that says that it is allowed to sell an
> electronic apparatus that uses a primary winding as a secondary winding - I
> spent a lot of time Googling this and I can't find anything.
I'm truly amazed that anyone woul
e
company paid the claim with no problems. Fortunately, smoke damage only and no
one hurt.
Jeff
-Original Message-
From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On
Behalf Of NeonJohn
Sent: Friday, October 02, 2015 7:38 PM
To: neonixie-l@googlegroups.com
Subjec
On 15-10-05 03:44 AM, Jim_Z wrote:
Also note that in the case of power supplies it's not important to UL
whether they really work or not- only that they perform to the UL
requirements which don't typically specify performance values.
Jim
Thinking of this thread bought back a converstaion I had
I once had to fix our neighbors' coffee grinder at Burning Man. I found that it
had a blown thermal fuse, probably because they were using a household coffee
grinder for an espresso bar which served dozens of cups a day.
Solution:
1. Bypass thermal fuse
2. Write on the case "For playa use only.
I do not know anything about this topic, that's why I asked.
I was told by a friend that the Low Voltage Directive in the EN61010
standard was the right place to look for answers, so I did and found some
details but I do not understand it all. I found
this http://www.ni.com/white-paper/2827/en/
I dont know if it's still common practice, but many radios and small TVs in
the US in the 1960's & 1970's had a 'hot-chassis' where one side of the AC
line was connected to the metal interior chassis. Obviously, these devices
had non-conductive (usually plastic) cases. Polarized cords supposedly
On 10/6/2015 3:50 PM, gregebert wrote:
I dont know if it's still common practice, but many radios and small
TVs in the US in the 1960's & 1970's had a 'hot-chassis' where one
side of the AC line was connected to the metal interior chassis.
Obviously, these devices had non-conductive (usually
On Tuesday, October 6, 2015 at 3:50:51 PM UTC-7, gregebert wrote:
>
> I dont know if it's still common practice, but many radios and small TVs
> in the US in the 1960's & 1970's had a 'hot-chassis' where one side of the
> AC line was connected to the metal interior chassis. Obviously, these
>
On 15-09-30 10:11 AM, gregebert wrote:
It's not the cost, but the availability. Ever since the demise of vacuum
tubes in the 1970's, high-ish voltage transformers have been getting
scarce.
If you are willing to PAY for them, there are reasonable units form
folks like Hammond. They have crept
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