Re: LF: W1VD amp help - more waveforms

[N1BUG <paul@n1bug.com>]

Jay,

The caps I used are polyester. Here's the datasheet:

https://www.mouser.com/datasheet/2/212/KEM_F3101_R82-1103738.pdf

It mentions timing applications, but I am no capacitor expert!
Comments appreciated. Mine are 5% tolerance marked 1nJ100.

I always measure resistors because I don't trust my eyes. The ones
used here measured about 14.98k on my Fluke DMM.

My proto board construction technique uses 'rows' of solder which
undoubtedly results in higher than usual stray C. However I would
expect it to be a few pf, not something that would throw the circuit
off this much.

Paul



On 04/11/2018 06:54 AM, jrusgrove@comcast.net wrote:
> Paul
>  
> The 1000 pF caps I used are mylar ... suitable for timing
> applications. Ceramic caps, if that's what you're using (sounds like
> it might be since they're Kemet), have rather poor value tolerance,
> value stability and temperature stability by comparison. Think I may
> have some extras that can be dropped in the mail today ... just say
> the word. If the resistors are cheap chinese you may want to
> actually measure them ... if you haven't already. Over time, the
> paint color difference between red and orange may not be so obvious.
> Been bit by that here ... more than once.
>  
> Jay W1VD
>  
>  
> 
>     *----- Original Message -----*
>     *From:* N1BUG <paul@n1bug.com <mailto:paul@n1bug.com>>
>     *Reply-To:* <rsgb_lf_group@blacksheep.org
>     <mailto:rsgb_lf_group@blacksheep.org>>
>     *To:* <rsgb_lf_group@blacksheep.org
>     <mailto:rsgb_lf_group@blacksheep.org>>
>     *Sent:* 4/10/2018 9:36:57 PM
>     *Subject:* Re: Fw: LF: W1VD amp help - more waveforms
>     --------------------------------------------------------------------
>     Aha! Jay
> 
>     See! Mine are *not* the same. In yours, one phase drops all the way
>     down, there's a slight dead zone, then the other starts coming up.
>     In mine, one is still on its way down when the other starts up. If
>     it's not an absolute red flag, it sure raises questions in my mind.
> 
>     Gates with Vdd off:
> 
>     http://www.n1bug.com/gates-10.jpg
> 
>     http://www.n1bug.com/gates-11.jpg
> 
>     Resistors and caps verified, caps by marking only since I can't
>     measure them. New KEMET caps purchased from Mouser for this project.
> 
>     Other curiosities might be that my gate rise time is slower than
>     yours and the little 'bobble' seems to occur at a lower voltage.
> 
>     Paul
> 
> 
> 
>     On 04/10/2018 09:08 PM, jrusgrove@comcast.net
>     <mailto:jrusgrove@comcast.net> wrote:
>     > Paul
>     >  
>     > Corrected links below.
>     >  
>     > www.w1vd.com/FETgate1.jpg <http://www.w1vd.com/FETgate1.jpg>
>     <http://www.w1vd.com/FETgate1.jpg>
>     >  
>     > www.w1vd.com/FETgate2.jpg <http://www.w1vd.com/FETgate2.jpg>
>     <http://www.w1vd.com/FETgate2.jpg>
>     >  
>     > Jay W1VD