voltage divider calcs
in [Design]
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From: Michael A. Terrell on 22 Apr 2010 20:10 Jim Thompson wrote: > > Michael A. Terrell wrote: > > > > You can still upgrade your XP computers with new motherboards RAM and > >hard drives, but who knows how long before MS drops all support & > >updates? > > Would that be a loss ?:-) That depends on whether you need a bug fixed. -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
From: Phil Hobbs on 22 Apr 2010 20:12 On 4/22/2010 12:56 PM, John Larkin wrote: > On Thu, 22 Apr 2010 09:20:19 -0700, Joerg<invalid(a)invalid.invalid> > wrote: > >> John Larkin wrote: >>> On Thu, 22 Apr 2010 17:14:54 +0300, >>> mikkosyrjalahti(a)Mikko-Syrjalahtis-MacBook.local (Mikko Syrjälahti) >>> wrote: >>> >>>> John Larkin<jjlarkin(a)highNOTlandTHIStechnologyPART.com> writes: >>>> >>>>> It's easier to use LT Spice to do a simple resistor string voltage >>>>> divider analysis than to use a calculator! Much easier if you want to >>>>> futz with values to hit some targets. >>>> I've been thinking of buying cheap coding to do javascript-based calculator >>>> for this. If anybody here would like to comment on most wanted features, I'll >>>> get it coded on rentacoder.com and will share the SW under BSD license. >>>> >>>> Basic calculations >>>> -Input ratio, find closest matches from E12-E96 series, with error >>>> -Input ratio+output impedance, do the same >>>> -Input resistance value, find closest series/parallel combination from E12-E96 series >>>> -Input SMD code, output value >>>> -Input value, output possible SMD codes >>>> -Input any two of R1, R2, Rp, Rs -> output others >>>> -Entry formats: 5120, 5k21, 0R1, 10M >>>> -Calculations performed right when entered, no reloads or anything needed >>>> >>>> Based on these: >>>> -Input voltage, output resistor combinations for TL431/TLV431 >>>> -Input voltage, output reasonable resistor combinations for LM317 >>>> -Input frequency, output reasonable (how to define ?) resistors+caps for 555 >>>> >>>> Bonuses: >>>> Cut&paste available resistors into textbox. Values stored to cookie (or database, which would >>>> require serverside software..). Do the previous stuff with these values. >>>> >>>> Forgot something ? >>> >>> >>> Here's RUGRAT, my resistor ratio program. It only considers parts that >>> we have in stock. >>> >>> ftp://jjlarkin.lmi.net/Rugrat.jpg >>> >> >> I like your rename for Internet Explorer. ROFL! Almost spilled my coffee ... > > Stupid Windows won't allow me to hide the ugly icon. Or to change the > icon to something more appropriate. Microsoft writes garbage. > >> >>> >>> Its output is a file, RUGRAT.TXT. I didn't do series/parallel combos, >>> because that's not as serious a problem. >>> >>> A voltage regulator calculator would be handy. It would have to cover >>> a lot of different parts. Then it should include switchers... >>> frequency, Ls, Cs.... >>> >>> I just use a cheat-sheet for Lm317/1117 type regs. Any time I need a >>> new voltage, I add it to the sheet. >>> >>> 555? People still use them? >>> >> >> 4 months ago I almost did for the first time in my life. Then I decided >> not to. I am sure it would have felt like a chef opening a package of >> Riceroni. > > I have to confess: I used a 555 once. Just once, honest. It ran off 12 > volts and ran a charge pump diode thingie to make -5. Forgive me. > > John > > Groucho could have done -40. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: krw on 22 Apr 2010 20:21 On Thu, 22 Apr 2010 20:10:03 -0400, "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote: > >Jim Thompson wrote: >> >> Michael A. Terrell wrote: >> > >> > You can still upgrade your XP computers with new motherboards RAM and >> >hard drives, but who knows how long before MS drops all support & >> >updates? >> >> Would that be a loss ?:-) > > > That depends on whether you need a bug fixed. Get real.
From: krw on 22 Apr 2010 20:20 On Thu, 22 Apr 2010 20:08:59 -0400, "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote: > >"krw(a)att.bizzzzzzzzzzzz" wrote: >> >> On Thu, 22 Apr 2010 19:32:58 -0400, "Michael A. Terrell" >> <mike.terrell(a)earthlink.net> wrote: >> >> > >> >Jim Thompson wrote: >> >> >> >> On Thu, 22 Apr 2010 19:23:17 -0400, "Michael A. Terrell" >> >> <mike.terrell(a)earthlink.net> wrote: >> >> >> >> > >> >> >Jim Thompson wrote: >> >> >> >> >> >> On Thu, 22 Apr 2010 09:56:26 -0700, John Larkin >> >> >> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >> >> >> >> >> [snip] >> >> >> > >> >> >> >Stupid Windows won't allow me to hide the ugly icon. Or to change the >> >> >> >icon to something more appropriate. Microsoft writes garbage. >> >> >> > >> >> >> [snip] >> >> >> >> >> >> Is that Windows 7 ?? >> >> >> >> >> >> I certainly can hide it with Windows XP. >> >> > >> >> > >> >> > I wonder if '7' is the IQ of the ad agency that's doing the new >> >> >commercials? >> >> >> >> I'm getting concerned with all the horror stories I'm hearing about >> >> Windows 7. >> >> >> >> My PC collection is getting aged (except for the laptop), so >> >> replacement is in the air :-( >> > >> > >> > You can still upgrade your XP computers with new motherboards RAM and >> >hard drives, but who knows how long before MS drops all support & >> >updates? >> >> They've got to get corporations (well, one anyway) to roll out '7' first. My >> computer at work was just replaced, with an XP box. > > > Did it replace a Win 95, or WFWG 3.1? ;-) We're not *quite* that bad. ;-) It was a P4 with XP. Office '07 killed it, so they finally bought me a new system. Why they wanted to go to Office '07, I'll never figure out. It sucks.
From: krw on 22 Apr 2010 20:24
On Thu, 22 Apr 2010 08:13:14 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 22 Apr 2010 17:14:54 +0300, >mikkosyrjalahti(a)Mikko-Syrjalahtis-MacBook.local (Mikko Syrjälahti) >wrote: > >>John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> writes: >> >>> It's easier to use LT Spice to do a simple resistor string voltage >>> divider analysis than to use a calculator! Much easier if you want to >>> futz with values to hit some targets. >> >>I've been thinking of buying cheap coding to do javascript-based calculator >>for this. If anybody here would like to comment on most wanted features, I'll >>get it coded on rentacoder.com and will share the SW under BSD license. >> >>Basic calculations >>-Input ratio, find closest matches from E12-E96 series, with error >>-Input ratio+output impedance, do the same >>-Input resistance value, find closest series/parallel combination from E12-E96 series >>-Input SMD code, output value >>-Input value, output possible SMD codes >>-Input any two of R1, R2, Rp, Rs -> output others >>-Entry formats: 5120, 5k21, 0R1, 10M >>-Calculations performed right when entered, no reloads or anything needed >> >>Based on these: >>-Input voltage, output resistor combinations for TL431/TLV431 >>-Input voltage, output reasonable resistor combinations for LM317 >>-Input frequency, output reasonable (how to define ?) resistors+caps for 555 >> >>Bonuses: >>Cut&paste available resistors into textbox. Values stored to cookie (or database, which would >>require serverside software..). Do the previous stuff with these values. >> >>Forgot something ? > > >Here's RUGRAT, my resistor ratio program. It only considers parts that >we have in stock. > >ftp://jjlarkin.lmi.net/Rugrat.jpg > > >Its output is a file, RUGRAT.TXT. I didn't do series/parallel combos, >because that's not as serious a problem. > >A voltage regulator calculator would be handy. It would have to cover >a lot of different parts. Then it should include switchers... >frequency, Ls, Cs.... > >I just use a cheat-sheet for Lm317/1117 type regs. Any time I need a >new voltage, I add it to the sheet. > >555? People still use them? Now you sound like Slowman. <...> |