Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > sci.electronics.design > #460255 > unrolled thread
| Started by | bitrex <bitrex@de.lete.earthlink.net> |
|---|---|
| First post | 2017-05-14 13:50 -0400 |
| Last post | 2017-05-16 14:05 +0000 |
| Articles | 20 on this page of 134 — 16 participants |
Back to article view | Back to sci.electronics.design
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
Page 4 of 7 — ← Prev page 1 2 3 [4] 5 6 7 Next page →
| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-05-15 18:41 +0000 |
| Message-ID | <XnsA7769579AC459idtokenpost@69.16.179.22> |
| In reply to | #460396 |
John Larkin <jjlarkin@highland_snip_technology.com> wrote: > On Mon, 15 May 2017 13:38:11 -0400, bitrex > <bitrex@de.lete.earthlink.net> wrote: > >>On 05/15/2017 01:28 PM, John Larkin wrote: >> >>>>> Snoop the input current of that buffer. At 20 MHz, the overall >>>>> current gain is less than 1. At 100 MHz, the current gain is about >>>>> 0.1. You'd be better off with a piece of wire. >>>> >>>> I'm not sure what "input current" you're looking at. I'm seeing an >>>> average current of around 600uA into the MOSFET gates at 100MHz. >>> >>> I put a 1 mohm resistor in series with the signal generator and >>> probed the current, with a sine wave signal input. Try it and see >>> what you get. >> >>How are the gate capacitances of the input MOSFETs supposed to be >>charged up and down with that fuckin' thing sitting in the way?! >> >>Fuck the circuit to hell and then complain it's bad?! Shit! :O > > mohm means milliohm, in SI units and in Spice. Megohm is MEG in spice. I don't know if caps are required in all versions. However, to measure current, all you need is a voltage source in series with zero volts output. Then plot the current through the device. But in LTspice, you can plot the current in any device using the current probe.
[toc] | [prev] | [next] | [standalone]
| From | John Larkin <jjlarkin@highland_snip_technology.com> |
|---|---|
| Date | 2017-05-15 13:19 -0700 |
| Message-ID | <583khclt0dbv5662siund118tnk8sgkkp2@4ax.com> |
| In reply to | #460397 |
On Mon, 15 May 2017 18:41:39 GMT, Steve Wilson <no@spam.com> wrote: >John Larkin <jjlarkin@highland_snip_technology.com> wrote: > >> On Mon, 15 May 2017 13:38:11 -0400, bitrex >> <bitrex@de.lete.earthlink.net> wrote: >> >>>On 05/15/2017 01:28 PM, John Larkin wrote: >>> >>>>>> Snoop the input current of that buffer. At 20 MHz, the overall >>>>>> current gain is less than 1. At 100 MHz, the current gain is about >>>>>> 0.1. You'd be better off with a piece of wire. >>>>> >>>>> I'm not sure what "input current" you're looking at. I'm seeing an >>>>> average current of around 600uA into the MOSFET gates at 100MHz. >>>> >>>> I put a 1 mohm resistor in series with the signal generator and >>>> probed the current, with a sine wave signal input. Try it and see >>>> what you get. >>> >>>How are the gate capacitances of the input MOSFETs supposed to be >>>charged up and down with that fuckin' thing sitting in the way?! >>> >>>Fuck the circuit to hell and then complain it's bad?! Shit! :O >> >> mohm means milliohm, in SI units and in Spice. > >Megohm is MEG in spice. I don't know if caps are required in all >versions. > >However, to measure current, all you need is a voltage source in series >with zero volts output. Then plot the current through the device. > >But in LTspice, you can plot the current in any device using the current >probe. The current probe is twitchy. I like to add visible current-shunt resistors to make it easier to probe. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
[toc] | [prev] | [next] | [standalone]
| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-05-15 20:46 +0000 |
| Message-ID | <XnsA776AA98AC34Eidtokenpost@69.16.179.22> |
| In reply to | #460423 |
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. This is not so bad, except you will have to turn it around to get the flow in the direction you want. Or you could simply add a minus sign to the plot to get it to the direction you want. These are simple things, but are part of the huge learning curve in spice. This is why I wish people would post working LTspice schematics instead of ASCII or hand-drawn schematics that most likely do not function.
[toc] | [prev] | [next] | [standalone]
| From | John Larkin <jjlarkin@highland_snip_technology.com> |
|---|---|
| Date | 2017-05-15 13:56 -0700 |
| Message-ID | <nf5khcttk1a708jms24plns5u4danbcdr2@4ax.com> |
| In reply to | #460427 |
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. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
[toc] | [prev] | [next] | [standalone]
| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-05-15 21:00 +0000 |
| Message-ID | <XnsA776AD15BF713idtokenpost@69.16.179.22> |
| In reply to | #460429 |
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. No matter how painful or inconvenient, LTspice is still orders of magnitude more useful than ASCII or hand-drawn schematics.
[toc] | [prev] | [next] | [standalone]
| From | John Larkin <jjlarkin@highland_snip_technology.com> |
|---|---|
| Date | 2017-05-15 16:46 -0700 |
| Message-ID | <cefkhclshedv6q9k9o04vhj289j6omdsni@4ax.com> |
| In reply to | #460430 |
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. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
[toc] | [prev] | [next] | [standalone]
| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-05-16 01:22 +0000 |
| Message-ID | <XnsA776D964B1236idtokenpost@69.16.179.23> |
| In reply to | #460439 |
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.
[toc] | [prev] | [next] | [standalone]
| From | John Larkin <jjlarkin@highland_snip_technology.com> |
|---|---|
| Date | 2017-05-16 11:16 -0700 |
| Message-ID | <kjemhcp1s47hq9n8qn50t6mispmj4pie5k@4ax.com> |
| In reply to | #460455 |
On Tue, 16 May 2017 01:22:14 GMT, Steve Wilson <no@spam.com> wrote: >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. The resistor is right at the base of the transistor. It's hard to miss. > >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. Node names are free in LT Spice. I name them something meaningful if I want to see the node name on a plot or a DC analysis. I can name the resistor RbQ2 or something, too. > >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. I'm not likely to forget, but Spice is useless in determining the value that will kill oscillations. It can establish that some value won't slow down normal operation too much. I tend to use 33 ohms. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
[toc] | [prev] | [next] | [standalone]
| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-05-16 18:55 +0000 |
| Message-ID | <XnsA77797DAD94C4idtokenpost@69.16.179.22> |
| In reply to | #460543 |
John Larkin <jjlarkin@highland_snip_technology.com> wrote: > On Tue, 16 May 2017 01:22:14 GMT, Steve Wilson <no@spam.com> wrote: >>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. > I'm not likely to forget, but Spice is useless in determining the > value that will kill oscillations. It can establish that some value > won't slow down normal operation too much. I tend to use 33 ohms. But you have already forgotten. Remember the tiny pcb you made where you didn't have enough room to add parasitic suppression resistors? As far as helping determine the value needed, finding a value that won't slow down normal operation too much is exactly what I meant. We agree.
[toc] | [prev] | [next] | [standalone]
| From | John Larkin <jjlarkin@highland_snip_technology.com> |
|---|---|
| Date | 2017-05-16 12:21 -0700 |
| Message-ID | <b6kmhchfvk914in3fk9oihq7c6th5hialo@4ax.com> |
| In reply to | #460553 |
On Tue, 16 May 2017 18:55:54 GMT, Steve Wilson <no@spam.com> wrote: >John Larkin <jjlarkin@highland_snip_technology.com> wrote: > >> On Tue, 16 May 2017 01:22:14 GMT, Steve Wilson <no@spam.com> wrote: > >>>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. > >> I'm not likely to forget, but Spice is useless in determining the >> value that will kill oscillations. It can establish that some value >> won't slow down normal operation too much. I tend to use 33 ohms. > >But you have already forgotten. Remember the tiny pcb you made where you >didn't have enough room to add parasitic suppression resistors? When you're doing fast stuff, and every picosecond is worth money, adding any resistor in the signal path, or wasting any space, is a defeat. > >As far as helping determine the value needed, finding a value that won't >slow down normal operation too much is exactly what I meant. > >We agree. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
[toc] | [prev] | [next] | [standalone]
| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-05-16 20:33 +0000 |
| Message-ID | <XnsA777A881F9A69idtokenpost@69.16.179.23> |
| In reply to | #460562 |
John Larkin <jjlarkin@highland_snip_technology.com> wrote: > On Tue, 16 May 2017 18:55:54 GMT, Steve Wilson <no@spam.com> wrote: >>But you have already forgotten. Remember the tiny pcb you made where you >>didn't have enough room to add parasitic suppression resistors? > > When you're doing fast stuff, and every picosecond is worth money, > adding any resistor in the signal path, or wasting any space, is a > defeat. Nice marketing, poor engineering. When you are trying to ship fast stuff, and it oscillates, that is a defeat. You have to fix it, and you had no room. You should have expected it and solved it before making lots of pcbs. Coupled high speed transistors or facing long leads is a potential disaster. I'll bet you check now.
[toc] | [prev] | [next] | [standalone]
| From | John Larkin <jjlarkin@highland_snip_technology.com> |
|---|---|
| Date | 2017-05-16 14:00 -0700 |
| Message-ID | <uspmhcls7q91po94rfr4oqas7kqncc4vn9@4ax.com> |
| In reply to | #460577 |
On Tue, 16 May 2017 20:33:54 GMT, Steve Wilson <no@spam.com> wrote: >John Larkin <jjlarkin@highland_snip_technology.com> wrote: > >> On Tue, 16 May 2017 18:55:54 GMT, Steve Wilson <no@spam.com> wrote: > >>>But you have already forgotten. Remember the tiny pcb you made where you >>>didn't have enough room to add parasitic suppression resistors? >> >> When you're doing fast stuff, and every picosecond is worth money, >> adding any resistor in the signal path, or wasting any space, is a >> defeat. > >Nice marketing, poor engineering. Design some picosecond stuff yourself. And show us. And don't be an asshole. > >When you are trying to ship fast stuff, and it oscillates, that is a >defeat. It got fixed and we got paid. > >You have to fix it, and you had no room. > >You should have expected it and solved it before making lots of pcbs. >Coupled high speed transistors or facing long leads is a potential >disaster. > >I'll bet you check now. I've been doing picosecond electronics for decades, and sold a ton of it... more as time goes on. Sometimes things happen on the first PCB rev of a difficult design. We fix it. No big deal. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
[toc] | [prev] | [next] | [standalone]
| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-05-16 21:21 +0000 |
| Message-ID | <XnsA777B0975990Aidtokenpost@69.16.179.23> |
| In reply to | #460580 |
John Larkin <jjlarkin@highland_snip_technology.com> wrote: > On Tue, 16 May 2017 20:33:54 GMT, Steve Wilson <no@spam.com> wrote: > >>John Larkin <jjlarkin@highland_snip_technology.com> wrote: >> >>> On Tue, 16 May 2017 18:55:54 GMT, Steve Wilson <no@spam.com> wrote: >> >>>>But you have already forgotten. Remember the tiny pcb you made where >>>>you didn't have enough room to add parasitic suppression resistors? >>> >>> When you're doing fast stuff, and every picosecond is worth money, >>> adding any resistor in the signal path, or wasting any space, is a >>> defeat. >> >>Nice marketing, poor engineering. > Design some picosecond stuff yourself. And show us. And don't be an > asshole. I was doing femtosecond stuff in 1970. Your insult about being an asshole has no effect. Stop being a jerk. >>When you are trying to ship fast stuff, and it oscillates, that is a >>defeat. > > It got fixed and we got paid. So what heppened to your picoseconds? >>You have to fix it, and you had no room. >> >>You should have expected it and solved it before making lots of pcbs. >>Coupled high speed transistors or facing long leads is a potential >>disaster. >> >>I'll bet you check now. > I've been doing picosecond electronics for decades, and sold a ton of > it... more as time goes on. Sometimes things happen on the first PCB > rev of a difficult design. We fix it. No big deal. As I said, you should have expected it, and you did not. So much for your claims of picosecond electronics. In fact, nothing you do is in picoseconds. Perhaps tenths of a nanosecond, but not much more. False claims, but they can make a lot of money.
[toc] | [prev] | [next] | [standalone]
| From | John Larkin <jjlarkin@highland_snip_technology.com> |
|---|---|
| Date | 2017-05-16 16:15 -0700 |
| Message-ID | <8o1nhclcfcno2sdutl5n9mma5uakhmm7kr@4ax.com> |
| In reply to | #460584 |
On Tue, 16 May 2017 21:21:49 GMT, Steve Wilson <no@spam.com> wrote: >John Larkin <jjlarkin@highland_snip_technology.com> wrote: > >> On Tue, 16 May 2017 20:33:54 GMT, Steve Wilson <no@spam.com> wrote: >> >>>John Larkin <jjlarkin@highland_snip_technology.com> wrote: >>> >>>> On Tue, 16 May 2017 18:55:54 GMT, Steve Wilson <no@spam.com> wrote: >>> >>>>>But you have already forgotten. Remember the tiny pcb you made where >>>>>you didn't have enough room to add parasitic suppression resistors? >>>> >>>> When you're doing fast stuff, and every picosecond is worth money, >>>> adding any resistor in the signal path, or wasting any space, is a >>>> defeat. >>> >>>Nice marketing, poor engineering. > >> Design some picosecond stuff yourself. And show us. And don't be an >> asshole. > >I was doing femtosecond stuff in 1970. Your insult about being an asshole >has no effect. Stop being a jerk. > >>>When you are trying to ship fast stuff, and it oscillates, that is a >>>defeat. >> >> It got fixed and we got paid. > >So what heppened to your picoseconds? > >>>You have to fix it, and you had no room. >>> >>>You should have expected it and solved it before making lots of pcbs. >>>Coupled high speed transistors or facing long leads is a potential >>>disaster. >>> >>>I'll bet you check now. > >> I've been doing picosecond electronics for decades, and sold a ton of >> it... more as time goes on. Sometimes things happen on the first PCB >> rev of a difficult design. We fix it. No big deal. > >As I said, you should have expected it, and you did not. So much for your >claims of picosecond electronics. > >In fact, nothing you do is in picoseconds. Perhaps tenths of a >nanosecond, but not much more. False claims, but they can make a lot of >money. https://dl.dropboxusercontent.com/u/53724080/Optos/95_ps_optical_pulse.jpg https://dl.dropboxusercontent.com/u/53724080/Circuits/Fast_Stuff/100_ps_steps.jpg https://dl.dropboxusercontent.com/u/53724080/Circuits/Fast_Stuff/NB7_Steps.jpg https://dl.dropboxusercontent.com/u/53724080/Circuits/Fast_Stuff/DSRD_neg-2KV.JPG -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
[toc] | [prev] | [next] | [standalone]
| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-05-16 23:58 +0000 |
| Message-ID | <XnsA777CB3235FD5idtokenpost@69.16.179.23> |
| In reply to | #460598 |
John Larkin <jjlarkin@highland_snip_technology.com> wrote: > On Tue, 16 May 2017 21:21:49 GMT, Steve Wilson <no@spam.com> wrote: > >>John Larkin <jjlarkin@highland_snip_technology.com> wrote: >> >>> On Tue, 16 May 2017 20:33:54 GMT, Steve Wilson <no@spam.com> wrote: >>> >>>>John Larkin <jjlarkin@highland_snip_technology.com> wrote: >>>> >>>>> On Tue, 16 May 2017 18:55:54 GMT, Steve Wilson <no@spam.com> >>>>> wrote: >>>> >>>>>>But you have already forgotten. Remember the tiny pcb you made >>>>>>where you didn't have enough room to add parasitic suppression >>>>>>resistors? >>>>> >>>>> When you're doing fast stuff, and every picosecond is worth money, >>>>> adding any resistor in the signal path, or wasting any space, is a >>>>> defeat. >>>> >>>>Nice marketing, poor engineering. >> >>> Design some picosecond stuff yourself. And show us. And don't be an >>> asshole. >> >>I was doing femtosecond stuff in 1970. Your insult about being an >>asshole has no effect. Stop being a jerk. >> >>>>When you are trying to ship fast stuff, and it oscillates, that is a >>>>defeat. >>> >>> It got fixed and we got paid. >> >>So what heppened to your picoseconds? >> >>>>You have to fix it, and you had no room. >>>> >>>>You should have expected it and solved it before making lots of >>>>pcbs. Coupled high speed transistors or facing long leads is a >>>>potential disaster. >>>> >>>>I'll bet you check now. >> >>> I've been doing picosecond electronics for decades, and sold a ton >>> of it... more as time goes on. Sometimes things happen on the first >>> PCB rev of a difficult design. We fix it. No big deal. >> >>As I said, you should have expected it, and you did not. So much for >>your claims of picosecond electronics. >> >>In fact, nothing you do is in picoseconds. Perhaps tenths of a >>nanosecond, but not much more. False claims, but they can make a lot >>of money. > > > https://dl.dropboxusercontent.com/u/53724080/Optos/95_ps_optical_pulse. > jpg > > https://dl.dropboxusercontent.com/u/53724080/Circuits/Fast_Stuff/100_ps > _steps.jpg > > https://dl.dropboxusercontent.com/u/53724080/Circuits/Fast_Stuff/NB7_St > eps.jpg > > https://dl.dropboxusercontent.com/u/53724080/Circuits/Fast_Stuff/DSRD_n > eg-2KV.JPG Like I said, tenths of a nansecond stuff, with a lot of jitter. Good marketing, poor engineering. But very few of your customers can tell the difference.
[toc] | [prev] | [next] | [standalone]
| From | John Larkin <jjlarkin@highland_snip_technology.com> |
|---|---|
| Date | 2017-05-16 17:51 -0700 |
| Message-ID | <jg7nhcl91b5nsoa0cak73jfi7lcsjielpq@4ax.com> |
| In reply to | #460605 |
On Tue, 16 May 2017 23:58:34 GMT, Steve Wilson <no@spam.com> wrote: >John Larkin <jjlarkin@highland_snip_technology.com> wrote: > >> On Tue, 16 May 2017 21:21:49 GMT, Steve Wilson <no@spam.com> wrote: >> >>>John Larkin <jjlarkin@highland_snip_technology.com> wrote: >>> >>>> On Tue, 16 May 2017 20:33:54 GMT, Steve Wilson <no@spam.com> wrote: >>>> >>>>>John Larkin <jjlarkin@highland_snip_technology.com> wrote: >>>>> >>>>>> On Tue, 16 May 2017 18:55:54 GMT, Steve Wilson <no@spam.com> >>>>>> wrote: >>>>> >>>>>>>But you have already forgotten. Remember the tiny pcb you made >>>>>>>where you didn't have enough room to add parasitic suppression >>>>>>>resistors? >>>>>> >>>>>> When you're doing fast stuff, and every picosecond is worth money, >>>>>> adding any resistor in the signal path, or wasting any space, is a >>>>>> defeat. >>>>> >>>>>Nice marketing, poor engineering. >>> >>>> Design some picosecond stuff yourself. And show us. And don't be an >>>> asshole. >>> >>>I was doing femtosecond stuff in 1970. Your insult about being an >>>asshole has no effect. Stop being a jerk. >>> >>>>>When you are trying to ship fast stuff, and it oscillates, that is a >>>>>defeat. >>>> >>>> It got fixed and we got paid. >>> >>>So what heppened to your picoseconds? >>> >>>>>You have to fix it, and you had no room. >>>>> >>>>>You should have expected it and solved it before making lots of >>>>>pcbs. Coupled high speed transistors or facing long leads is a >>>>>potential disaster. >>>>> >>>>>I'll bet you check now. >>> >>>> I've been doing picosecond electronics for decades, and sold a ton >>>> of it... more as time goes on. Sometimes things happen on the first >>>> PCB rev of a difficult design. We fix it. No big deal. >>> >>>As I said, you should have expected it, and you did not. So much for >>>your claims of picosecond electronics. >>> >>>In fact, nothing you do is in picoseconds. Perhaps tenths of a >>>nanosecond, but not much more. False claims, but they can make a lot >>>of money. >> >> >> https://dl.dropboxusercontent.com/u/53724080/Optos/95_ps_optical_pulse. >> jpg >> >> https://dl.dropboxusercontent.com/u/53724080/Circuits/Fast_Stuff/100_ps >> _steps.jpg >> >> https://dl.dropboxusercontent.com/u/53724080/Circuits/Fast_Stuff/NB7_St >> eps.jpg >> >> https://dl.dropboxusercontent.com/u/53724080/Circuits/Fast_Stuff/DSRD_n >> eg-2KV.JPG > >Like I said, tenths of a nansecond stuff, with a lot of jitter. > >Good marketing, poor engineering. But very few of your customers can tell >the difference. The NIF timing system had about 2000 endpoints spread around the biggest laser in the world. Jitter across the system was about 3 ps RMS, or maybe it would have been better if we'd had better oscilloscopes. https://dl.dropboxusercontent.com/u/53724080/NIF3.jpg We could do better today. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
[toc] | [prev] | [next] | [standalone]
| From | pcdhobbs@gmail.com |
|---|---|
| Date | 2017-05-16 16:30 -0700 |
| Message-ID | <b65a3191-8663-4a60-9619-578afe9cec89@googlegroups.com> |
| In reply to | #460584 |
>I was doing femtosecond stuff in 1970. Do tell. "Femtosecond stuff" such as reading the newspaper by 600 THz light, maybe? I'm pretty sure I'm the only one in this group who has actually built electronics that respond on fs time scales (optical antennas coupled to metal-insulator-metal tunnel diodes--basically crystal radios for light). Picosecond lasers were the state of the art in the late '80s. One or two groups had used pulse compression to make pulses at the 10-20 fs level as a hero experiment by then, but that sure wasn't happening in 1970. So what "femtosecond stuff" were you doing in 1970? Cheers Phil Hobbs
[toc] | [prev] | [next] | [standalone]
| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-05-17 00:16 +0000 |
| Message-ID | <XnsA777CE3B1572Eidtokenpost@69.16.179.23> |
| In reply to | #460601 |
pcdhobbs@gmail.com wrote: >>I was doing femtosecond stuff in 1970. > > Do tell. "Femtosecond stuff" such as reading the newspaper by 600 THz > light, maybe? > > I'm pretty sure I'm the only one in this group who has actually built > electronics that respond on fs time scales (optical antennas coupled > to metal-insulator-metal tunnel diodes--basically crystal radios for > light). > > Picosecond lasers were the state of the art in the late '80s. One or > two groups had used pulse compression to make pulses at the 10-20 fs > level as a hero experiment by then, but that sure wasn't happening in > 1970. > > So what "femtosecond stuff" were you doing in 1970? > > Cheers > > Phil Hobbs I have a great deal of respect for your engineering capability. It is probably second to none in optics. I was in a different industry. I designed products for the hard disk industry. I made timing measurements in production test to 100fs. This was essential to meet the accuracy and linearity requirements needed. I was the only person in the industry who could do this. I made millions. There is a big difference between 100fs risetime and several tens of picoseconds of rms jitter. You should make some tutorials to make this clear to people. You have posted a number of simple equations that describe this. I chide Larkin on his "picosecond electronics". Do you accept his claims? I thought not.
[toc] | [prev] | [next] | [standalone]
| From | pcdhobbs@gmail.com |
|---|---|
| Date | 2017-05-16 18:05 -0700 |
| Message-ID | <ab19b9d9-a0bb-4b2b-82d0-ecbdfa11e396@googlegroups.com> |
| In reply to | #460608 |
>I chide Larkin on his "picosecond electronics". Do you accept his claims? >I thought not. You really shouldn't let your temper lead you into putting words in people's mouths. I have a few of JL's products in my lab. My favourite is the P400 digital delay generator, which I use a fair amount--it's my go-to pulse generator for everything. It's similar to an SRS delay generator I used to have except that its jitter is a good 30 dB less (~5 ps vs ~200 ps). That sort of improvement doesn't happen by accident. You claim hundreds-of-femtoseconds jitter numbers for hard disks in 1970. Even if that were so, that's "sub-picosecond" and not "femtosecond". However the state of the art in hard drives in 1970 was nowhere near that jitter level. The 1973 IBM "Winchester" drive had a data transfer rate of less than 1 Mb/s. Sub-picosecond jitter? Really? Like 120-odd dB down? I seriously doubt that available test equipment could have made that measurement, even if by some miracle it was that good. How did you measure it? Cheers Phil Hobbs
[toc] | [prev] | [next] | [standalone]
| From | John Larkin <jjlarkin@highlandtechnology.com> |
|---|---|
| Date | 2017-05-16 20:05 -0700 |
| Message-ID | <v9fnhcd5fs8lh8svus6lfi5cgiva3lhn65@4ax.com> |
| In reply to | #460617 |
On Tue, 16 May 2017 18:05:10 -0700 (PDT), pcdhobbs@gmail.com wrote: >>I chide Larkin on his "picosecond electronics". Do you accept his claims? > >>I thought not. > >You really shouldn't let your temper lead you into putting words in people's mouths. > >I have a few of JL's products in my lab. My favourite is the P400 digital delay generator, which I use a fair amount--it's my go-to pulse generator for everything. It's similar to an SRS delay generator I used to have except that its jitter is a good 30 dB less (~5 ps vs ~200 ps). That sort of improvement doesn't happen by accident. When we get around to doing a next gen, I'll send you one. The P400 works fine, but it is sort of ugly. A DDG is a wonderful thing to have around, a real Time Machine. -- John Larkin Highland Technology, Inc lunatic fringe electronics
[toc] | [prev] | [next] | [standalone]
Page 4 of 7 — ← Prev page 1 2 3 [4] 5 6 7 Next page →
Back to top | Article view | sci.electronics.design
csiph-web