Re: An actual circuit

"john larkin" <jl@650pot.com> wrote in message
news:phk15jlc055d4p4b1qlicodl16v85u00d9@4ax.com...

On Fri, 24 May 2024 11:59:31 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
>

"john larkin" <jl@650pot.com> wrote in message
news:bk815jh3skuecf1tap8o41rpgdh5kkq8o5@4ax.com...

On Thu, 23 May 2024 13:06:46 -0700, john larkin <jl@650pot.com> wrote:
>

On Thu, 23 May 2024 15:35:00 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
>

I was having a conversation with a younger person who seemed to be of
the
view that to make an LED flash you would need something to decide when
it
should be on or off. So that would be some kind of software or digital
system.

...

>
If R2 and R6 are both 3.3k then LTSpice says it slowly drifts into
operation
after 40 seconds.
But why does it go one way and not the other?
Is that an artefact of asymmetry in the simulation?
Or is there some hidden asymmetry in the circuit I'm not seeing when R2 is
3.3k?
>

>
Yes, it is mysterious. Set both drain resistors to 3.3K and zoom way
up on the two source voltages for the first 20 seconds.

Why the crossover at 15 seconds?
I think reliable startup of the simulated symmetrical version has to be a
simulation artefact.

Now I'm curious what the real circuit would do.
I may have suitable parts.

>
LT Spice may have some hidden asymmetry. It has to do math
sequentially, maybe.
>
In real life, parts will be plenty asymmetric. Especially jfets.