I realize this was vanagon related when it began, and I rarely make this
observation, but this is the third or fourth time in recent memory that
we've had to endure this kind of obscure egg-headery, particularly regarding
electronics.
If y'all actually solve some need as a result of these discussions, then
that's all good, but could you guys please take the discussion itself
off-list? It gets pretty dense and wearying after a while.

Cya,
Robert

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Rocket J Squirrel
Sent: Tuesday, September 29, 2009 9:23 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: ARRRGGGHHH Re: Tantalum capacitors to stop blinking temp LED

Ah well then -- never mind.
--
Mike "Rocket J Squirrel" Elliott
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Westrailia: (Ladybug Trailer company, San Juan Capistrano, Calif.)
Bend, OR
KG6RCR

On 9/29/2009 9:03 AM David Beierl wrote:

> At 10:48 AM 9/29/2009, Rocket J Squirrel wrote:
>> That's not the same as a 0pf capacitor. It's the same as a resistor, and
>> if the capacitor is being charged through another resistor until it
>> reaches the shutoff trigger voltage, and that capacitor is paralleled
>> with
>> a resistor to model the internal leakage (or schmutz on the board, the
>> proposed "external" portion of the leakage) then you got a voltage
>> divider
>> which will prevent the voltage at the top of the cap from ever reaching
>> blink-o-matic shutoff voltage.
>
> Mike's talking about removing the cap entirely, so aside from the fact
> that the newer level controllers *need* that timed blink, the only issue
> would be leakage across the board, which isn't enough to matter by
> itself.  The current source for the cap would drive the chip high
> directly.  Of course that might inhibit the blink completely, probably
> would I think -- can't remember the circuit well enough.  But it's moot
> because of the controllers.
>
> :-)
> d
>
>