Re: LF: W1VD amp help - more waveforms

["jrusgrove@comcast.net" <jrusgrove@comcast.net>]

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>

Reply-To: <rsgb_lf_group@blacksheep.org>

To: <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 wrote:
> Paul
>  
> Corrected links below.
>  
> www.w1vd.com/FETgate1.jpg <http://www.w1vd.com/FETgate1.jpg>
>  
> www.w1vd.com/FETgate2.jpg <http://www.w1vd.com/FETgate2.jpg>
>  
> Jay W1VD