Groups > sci.electronics.design > #460455

Re: Fast buffer idea

Newsgroups	sci.electronics.design
Subject	Re: Fast buffer idea
From	Steve Wilson <no@spam.com>
References	(7 earlier) <583khclt0dbv5662siund118tnk8sgkkp2@4ax.com> <XnsA776AA98AC34Eidtokenpost@69.16.179.22> <nf5khcttk1a708jms24plns5u4danbcdr2@4ax.com> <XnsA776AD15BF713idtokenpost@69.16.179.22> <cefkhclshedv6q9k9o04vhj289j6omdsni@4ax.com>
Message-ID	<XnsA776D964B1236idtokenpost@69.16.179.23> (permalink)
Organization	http://www.NewsDemon.com
Date	2017-05-16 01:22 +0000

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John Larkin <jjlarkin@highland_snip_technology.com> wrote:

> On Mon, 15 May 2017 21:00:54 GMT, Steve Wilson <no@spam.com> wrote:

>>John Larkin <jjlarkin@highland_snip_technology.com> wrote:

>>> On Mon, 15 May 2017 20:46:14 GMT, Steve Wilson <no@spam.com> wrote:

>>>>John Larkin <jjlarkin@highland_snip_technology.com> wrote:

>>>>> The current probe is twitchy. I like to add visible current-shunt
>>>>> resistors to make it easier to probe. 

>>>>Nothing wrong with that, except you have to add separate node names 
to
>>>>either side of the resistor. Then instead of plotting Ib(Q2) you will
>>>>plot I(R12). The polarity will depend on the orientation of the
>>>>resistor. 

>>> LT Spice defaults to getting that backwards.

>>So plot the twitchy base, emitter or collector current, and add a minus 
>>sign if needed to make it correspond with the waveform.

> I just flip the resistor.

As above. Now you are plotting I(Rxx) instead of IB(Qx). Rxx may be a lot 
harder to find on the schematic than Qx. Wases your time looking.

Also the extra part takes up more space and requires another node name so 
you are not trying to plot V(n00x), which may change as soon as you add 
or remove another node. Good luck trying to find the original node that 
you wanted to plot. Wastes your time looking.

There are cases where an extra resistor is actually needed, such as a 
base parasitic resistor or in the gate of a fast MOSFET. These can remind 
you to include the resistor in the pcb layout, and help determine the 
value needed in the circuit. In the case of the emitter or collector, it 
usually goes to ground or to another component, so you don't need to add 
another resistor to monitor the current.

Thread

Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 13:50 -0400
  Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 11:27 -0700
    Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-14 19:19 +0000
      Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 15:24 -0400
      Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 12:54 -0700
        Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:02 -0400
          Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 13:10 -0700
            Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:16 -0400
              Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:18 -0400
              Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 14:14 -0700
              Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-15 19:51 +0100
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 13:17 -0700
                Re: Fast buffer idea Clifford Heath <clifford.heath@gmail.com> - 2017-05-17 09:14 +1000
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 16:26 -0700
                Re: Fast buffer idea "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-05-17 02:04 -0500
        Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-14 20:26 +0000
          Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:31 -0400
          Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:43 -0400
          Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 14:17 -0700
            Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-14 21:53 +0000
              Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 16:14 -0700
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 19:59 -0400
                Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 20:06 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 00:16 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 20:10 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 03:28 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 20:48 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 04:17 +0000
        Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 07:56 +0000
          Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 06:58 -0400
            Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 12:59 +0000
          Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-15 07:01 -0700
            Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 10:09 -0400
              Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 10:18 -0400
                Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-15 08:56 -0700
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 16:02 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 10:33 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 18:15 +0000
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 14:25 -0400
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 14:26 -0400
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 16:24 +0000
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 16:36 +0000
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 17:18 +0000
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 13:30 -0400
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 18:07 +0000
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 19:19 +0000
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 19:45 +0000
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-16 08:33 +0000
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 19:13 +0000
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 15:33 -0400
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-16 08:16 +0000
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-16 22:10 -0400
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 19:10 +0000
              Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-15 08:55 -0700
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 12:51 -0400
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 12:56 -0400
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 13:05 -0400
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 10:28 -0700
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 13:38 -0400
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 11:29 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 18:41 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 13:19 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 20:46 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 13:56 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 21:00 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 16:46 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-16 01:22 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 11:16 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-16 18:55 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 12:21 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-16 20:33 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 14:00 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-16 21:21 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 16:15 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-16 23:58 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-16 17:51 -0700
                Re: Fast buffer idea pcdhobbs@gmail.com - 2017-05-16 16:30 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-17 00:16 +0000
                Re: Fast buffer idea pcdhobbs@gmail.com - 2017-05-16 18:05 -0700
                Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-16 20:05 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-25 01:13 +0000
                Re: Fast buffer idea Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-05-24 21:43 -0400
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-30 03:16 +0000
                Re: Fast buffer idea Ralph Barone <ralph@invalid.com> - 2017-05-17 02:26 +0000
                Re: Fast buffer idea Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2017-05-17 08:34 +0200
                Re: Fast buffer idea Ralph Barone <ralph@invalid.com> - 2017-05-17 14:31 +0000
                Re: Fast buffer idea Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-05-17 10:39 -0400
                Re: Fast buffer idea Reinhardt Behm <rbehm@hushmail.com> - 2017-05-17 23:02 +0800
                Re: Fast buffer idea Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2017-05-16 21:24 +0200
                Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-16 20:12 -0700
                Re: Fast buffer idea Winfield Hill <hill@rowland.harvard.edu> - 2017-05-25 04:38 -0700
                Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-25 07:28 -0700
                Re: Fast buffer idea "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-05-26 08:54 -0500
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-26 14:14 +0000
                Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-26 07:21 -0700
                Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-16 20:27 +0100
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 15:05 -0400
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 15:19 -0400
                Re: Fast buffer idea John Larkin <jjlarkin@highland_snip_technology.com> - 2017-05-15 13:21 -0700
                Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 20:56 +0000
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 17:37 -0400
              Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-15 19:50 +0100
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 19:25 +0000
                Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-16 20:19 +0100
            Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 14:33 +0000
              Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 13:15 -0400
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-15 19:05 +0000
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-15 15:38 -0400
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-16 08:12 +0000
                Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-16 18:47 +0000
                Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-16 21:52 -0400
                Re: Fast buffer idea Winfield Hill <hill@rowland.harvard.edu> - 2017-05-25 05:05 -0700
                Re: Fast buffer idea pcdhobbs@gmail.com - 2017-05-25 05:42 -0700
                Re: Fast buffer idea Winfield Hill <hill@rowland.harvard.edu> - 2017-05-25 05:49 -0700
                Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-25 08:10 -0700
                Re: Fast buffer idea Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2017-05-25 15:01 +0200
      Re: Fast buffer idea "John Miles, KE5FX" <jmiles@gmail.com> - 2017-05-14 18:53 -0700
        Re: Fast buffer idea Steve Wilson <no@spam.com> - 2017-05-15 02:45 +0000
    Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 15:23 -0400
  Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-14 20:28 +0100
    Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:00 -0400
    Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 16:10 -0400
      Re: Fast buffer idea Winfield Hill <hill@rowland.harvard.edu> - 2017-05-14 17:58 -0700
        Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-14 23:13 -0400
        Re: Fast buffer idea Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-05-16 17:27 -0700
          Re: Fast buffer idea Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-05-16 17:34 -0700
      Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-14 20:14 -0700
        Re: Fast buffer idea "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-05-15 19:42 +0100
  Re: Fast buffer idea "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-05-16 03:29 -0500
    Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-16 06:57 -0700
      Re: Fast buffer idea bitrex <bitrex@de.lete.earthlink.net> - 2017-05-16 22:47 -0400
        Re: Fast buffer idea John Larkin <jjlarkin@highlandtechnology.com> - 2017-05-16 20:18 -0700
          Re: Fast buffer idea "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-05-17 02:22 -0500
    Re: Fast buffer idea Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-16 14:05 +0000

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