Simulating a variable resistance input with LTSpice?
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From: Joerg on 16 Apr 2010 09:03 neddie wrote: > On Apr 13, 7:58 pm, Joerg <inva...(a)invalid.invalid> wrote: >> Hello Folks, >> >> Got stuck when trying to simulate an NTC. This temperature-variant >> resistor will be the only variable input so ".STEP" and stuff do not cut >> it because that only overlays multiple curve in an AC or DC simulation. >> I want just one curve: Output of my circuit versus varying NTC resistor >> value. >> >> Tried to make a voltage dependent resistor this way: >> >> http://www.electro-tech-online.com/attachments/general-electronics-ch... >> >> It works but is incredibly slow. Any better ideas? >> >> -- >> Regards, Joerg >> >> http://www.analogconsultants.com/ >> >> "gmail" domain blocked because of excessive spam. >> Use another domain or send PM. > > .step temp 0 100 10 > , with simulation command set to DC op point > or am I missing something here. > Rob The it drew a staggered set of curves but I needed only one graph. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Jim Thompson on 16 Apr 2010 10:45 On Fri, 16 Apr 2010 06:03:50 -0700, Joerg <invalid(a)invalid.invalid> wrote: >neddie wrote: >> On Apr 13, 7:58 pm, Joerg <inva...(a)invalid.invalid> wrote: >>> Hello Folks, >>> >>> Got stuck when trying to simulate an NTC. This temperature-variant >>> resistor will be the only variable input so ".STEP" and stuff do not cut >>> it because that only overlays multiple curve in an AC or DC simulation. >>> I want just one curve: Output of my circuit versus varying NTC resistor >>> value. >>> >>> Tried to make a voltage dependent resistor this way: >>> >>> http://www.electro-tech-online.com/attachments/general-electronics-ch... >>> >>> It works but is incredibly slow. Any better ideas? >>> >>> -- >>> Regards, Joerg >>> >>> http://www.analogconsultants.com/ >>> >>> "gmail" domain blocked because of excessive spam. >>> Use another domain or send PM. >> >> .step temp 0 100 10 >> , with simulation command set to DC op point >> or am I missing something here. >> Rob > > >The it drew a staggered set of curves but I needed only one graph. What exactly are you trying to do, Joerg? Get a DC output versus temperature? Or what? You're showing less and less clarity as you go :-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy
From: Joerg on 16 Apr 2010 11:14 Jim Thompson wrote: > On Fri, 16 Apr 2010 06:03:50 -0700, Joerg <invalid(a)invalid.invalid> > wrote: > >> neddie wrote: >>> On Apr 13, 7:58 pm, Joerg <inva...(a)invalid.invalid> wrote: >>>> Hello Folks, >>>> >>>> Got stuck when trying to simulate an NTC. This temperature-variant >>>> resistor will be the only variable input so ".STEP" and stuff do not cut >>>> it because that only overlays multiple curve in an AC or DC simulation. >>>> I want just one curve: Output of my circuit versus varying NTC resistor >>>> value. >>>> >>>> Tried to make a voltage dependent resistor this way: >>>> >>>> http://www.electro-tech-online.com/attachments/general-electronics-ch... >>>> >>>> It works but is incredibly slow. Any better ideas? >>>> >>>> -- >>>> Regards, Joerg >>>> >>>> http://www.analogconsultants.com/ >>>> >>>> "gmail" domain blocked because of excessive spam. >>>> Use another domain or send PM. >>> .step temp 0 100 10 >>> , with simulation command set to DC op point >>> or am I missing something here. >>> Rob >> >> The it drew a staggered set of curves but I needed only one graph. > > What exactly are you trying to do, Joerg? Get a DC output versus > temperature? Or what? You're showing less and less clarity as you go > :-) > Yes, a DC output versus temperature as _one_ contiguous graph. Not as a set of graphs like what the .step function usually does. But as I said, it's now all done and done, using a few sheets of paper and ye olde pencil :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Jim Thompson on 16 Apr 2010 11:32 On Fri, 16 Apr 2010 08:14:22 -0700, Joerg <invalid(a)invalid.invalid> wrote: >Jim Thompson wrote: >> On Fri, 16 Apr 2010 06:03:50 -0700, Joerg <invalid(a)invalid.invalid> >> wrote: >> >>> neddie wrote: >>>> On Apr 13, 7:58 pm, Joerg <inva...(a)invalid.invalid> wrote: >>>>> Hello Folks, >>>>> >>>>> Got stuck when trying to simulate an NTC. This temperature-variant >>>>> resistor will be the only variable input so ".STEP" and stuff do not cut >>>>> it because that only overlays multiple curve in an AC or DC simulation. >>>>> I want just one curve: Output of my circuit versus varying NTC resistor >>>>> value. >>>>> >>>>> Tried to make a voltage dependent resistor this way: >>>>> >>>>> http://www.electro-tech-online.com/attachments/general-electronics-ch... >>>>> >>>>> It works but is incredibly slow. Any better ideas? >>>>> >>>>> -- >>>>> Regards, Joerg >>>>> >>>>> http://www.analogconsultants.com/ >>>>> >>>>> "gmail" domain blocked because of excessive spam. >>>>> Use another domain or send PM. >>>> .step temp 0 100 10 >>>> , with simulation command set to DC op point >>>> or am I missing something here. >>>> Rob >>> >>> The it drew a staggered set of curves but I needed only one graph. >> >> What exactly are you trying to do, Joerg? Get a DC output versus >> temperature? Or what? You're showing less and less clarity as you go >> :-) >> > >Yes, a DC output versus temperature as _one_ contiguous graph. Not as a >set of graphs like what the .step function usually does. > >But as I said, it's now all done and done, using a few sheets of paper >and ye olde pencil :-) ..DC TEMP START STOP INCREMENT eg ..DC TEMP -40 85 0.1 ..STEP is for performing other types of simulations, repeatedly, with different "parameter" values for each simulation. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy
From: Helmut Sennewald on 16 Apr 2010 15:22
"Joerg" <invalid(a)invalid.invalid> schrieb im Newsbeitrag news:82rd6nFsp9U1(a)mid.individual.net... > Jim Thompson wrote: >> On Fri, 16 Apr 2010 06:03:50 -0700, Joerg <invalid(a)invalid.invalid> >> wrote: >> >>> neddie wrote: >>>> On Apr 13, 7:58 pm, Joerg <inva...(a)invalid.invalid> wrote: >>>>> Hello Folks, >>>>> >>>>> Got stuck when trying to simulate an NTC. This temperature-variant >>>>> resistor will be the only variable input so ".STEP" and stuff do not >>>>> cut >>>>> it because that only overlays multiple curve in an AC or DC >>>>> simulation. >>>>> I want just one curve: Output of my circuit versus varying NTC >>>>> resistor >>>>> value. >>>>> >>>>> Tried to make a voltage dependent resistor this way: >>>>> >>>>> http://www.electro-tech-online.com/attachments/general-electronics-ch... >>>>> >>>>> It works but is incredibly slow. Any better ideas? >>>>> >>>>> -- >>>>> Regards, Joerg >>>>> >>>>> http://www.analogconsultants.com/ >>>>> >>>>> "gmail" domain blocked because of excessive spam. >>>>> Use another domain or send PM. >>>> .step temp 0 100 10 >>>> , with simulation command set to DC op point >>>> or am I missing something here. >>>> Rob >>> >>> The it drew a staggered set of curves but I needed only one graph. >> >> What exactly are you trying to do, Joerg? Get a DC output versus >> temperature? Or what? You're showing less and less clarity as you go >> :-) >> > > Yes, a DC output versus temperature as _one_ contiguous graph. Not as a > set of graphs like what the .step function usually does. > > But as I said, it's now all done and done, using a few sheets of paper and > ye olde pencil :-) > > -- > Regards, Joerg > > http://www.analogconsultants.com/ > > "gmail" domain blocked because of excessive spam. > Use another domain or send PM. Hello Joerg, If you use ..step TEMP 0 100 1 together with only ..OP You will get only one graph. There is one drawback with the global TEMP. If you have opamp models around, they may suffer because of this varying TEMP. Opamp models are mostly made for only the standard temperature in SPICE (27�C). If this is the case with your circuit, I can make you another example where the NTC-resistor is controlled by a free variable, e.g. TMP. Best regards, Helmut |