Re: A newly working Commodore 720 - many questions...

From: MikeS <dm561_at_torfree.net>
Date: Wed, 22 Feb 2012 14:31:50 -0500
Message-ID: <5E591A7C8F8D4D0883132F33900D5FAD@vl420mt>
----- Original Message ----- 
From: "Jim Brain" <brain@jbrain.com>
Sent: Wednesday, February 22, 2012 1:57 PM

> On 2/16/2012 10:49 AM, Gerrit Heitsch wrote:
>>
>>    D1 = 1N4148
> Why is D1 needed?  In the reverse mode, the optocouple won't conduct, so
> they're no concerns.
--
Maximum reverse voltage of LEDs is generally very low, 6V in the case of 
4Nxx optocouplers.
--
>>    C1 = 10 nF
> I assume it's there to stretch the cycle.  Given the 6.3V transformer
> will have enough forward voltage for most of the half cycle, is the cap
> really even needed?
--
Just guessing, maybe to filter out line noise?

mike 


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