voltage divider calcs
in [Design]
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From: Jan Panteltje on 22 Apr 2010 11:01 On a sunny day (Thu, 22 Apr 2010 17:14:54 +0300) it happened mikkosyrjalahti(a)Mikko-Syrjalahtis-MacBook.local (Mikko > >Forgot something ? Trimpots ;-)
From: John Larkin on 22 Apr 2010 11:13 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? The bummer about the standard E12-E96 values is that the same ratios keep appearing/not appearing. Throwing in a few of the oddball Susumu parts helps break that up. John
From: Joerg on 22 Apr 2010 12:20 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 ... > > 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. > The bummer about the standard E12-E96 values is that the same ratios > keep appearing/not appearing. Throwing in a few of the oddball Susumu > parts helps break that up. > Like a spectrogram where you never get anything between the usual lines? -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: John Larkin on 22 Apr 2010 12:56 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
From: Tim Williams on 22 Apr 2010 13:27
"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:1iv0t5l56oat9ahhjkmlba6vo7aaj9h312(a)4ax.com... >>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. Actually, you can. Desktop Properties. It can also be disabled. Ironically, I already disabled mine, and some time between June last year and now, it disappeared. http://myweb.msoe.edu/williamstm/Images/Desktop.gif Weird, it wasn't renamed "Internet Exploder" at the time. Although Windows Exploder was. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms |