Mailing list archives : pcb-rnd

From:Robin Laing <>
Date:Mon, 6 Jul 2020 10:09:43 -0600
Subject:Re: [pcb-rnd] Off topic (maybe) - Spice simulator
in-reply-to:4232 from Evan Foss <>
Hi Evan,
I fully agree with you.  I have a large amount of components at home and 
can test almost anything.
High Voltages systems are fun.  I had to repair some HV systems for 
someone a few years ago.  50KV and insulation was the breaking down as 
well as other operator issues.  Found out that JB Weld is a pretty good 
insulator and has the strength where needed.  Also a high temp gasket 
compound works well as combination adhesive and insulator.
On 29/06/2020 16:40, Evan Foss wrote:
> Hi Robin,
> I understand. COVID-19 has me effectively locked out of our lab. I
> guess I am lucky in that I at least have a pile of test equipment to
> use.
> I ask about the experimental setup because it's easy for students to
> mess up without realizing it on experimental setup. Tektronix CRT
> oscilloscopes have a common fault of turning off with a pop because
> the older flyback output cables can have moisture in their insulation
> which can arc through without leaving much of a mark to see with the
> naked eye. I could see an experimental setup designed to arc having
> this issue.
> I used multisim in college and actually it's predecessor Electronics
> WorkBench in middle school. It's ok but I wish they published more
> complete errata for all the models and the spice engine.
> Evan
> Evan
> On Mon, Jun 29, 2020 at 5:18 PM Robin Laing <> wrote:
>> Hello, Evan,
>> I really don't know what the setup is.  I do know that it is to generate
>> a timed, high energy pulse but due to COVID-19 and working at home, I am
>> not deeply involved in that phase of the project.  It is in the hands of
>> an engineer (Not Electronics).
>> Some discussion was brought up about simulation issues in Multisim in a
>> teleconference and I thought I would ask the list.  From teleconference
>> today, information that members of this group provided have been helpful
>> but I don't know in what way.
>> Robin
>> On 26/06/2020 15:27, Evan Foss wrote:
>>> What does your experimental setup look like? I am picturing something
>>> like a digital version of Tesla's lab in NY.
>>> On Fri, Jun 26, 2020 at 3:46 PM Robin Laing <> wrote:
>>>> On 24/06/2020 13:48, gene glick wrote:
>>>>> Ok,  I see your point and I agree.  I was just trying to get a 1st order
>>>>> approximation for the simulator.
>>>>> In my experience,  and probably originally preached by Bob Pease, don't
>>>>> get lost in the simulator. Get close enough,  then build it.
>>>>> You can spend a lifetime trying to get an exact response from
>>>>> simulation... trying to work out everything virtually... only to find in
>>>>> the real world that it behaves a lot different.
>>>>> Spice takes a long time to run.  Dumb down your circuits enough to get
>>>>> at the most important stuff... then prototype it.
>>>> I wish I could beat this into some peoples brains.  They expect models
>>>> to be perfect all the time.
>>>> I have been told that if the model isn't working, then we have to look
>>>> at different tools to model it better.  I think that is part of the
>>>> issue in this case.  Simulation says one thing, real world says
>>>> something else.  In our case, the real world is the problem and we do
>>>> need to be closer to the simulation.  I am thinking that the real world
>>>> is related to the way that the circuit was constructed as a big part to
>>>> the issues.
>>>> Robin

Reply subtree:
4248 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Robin Laing <>