LTspice
in [Design]
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From: John Larkin on 5 Oct 2007 13:53 On Fri, 5 Oct 2007 09:49:44 -0700, "Joel Kolstad" <JKolstad71HatesSpam(a)yahoo.com> wrote: >"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >news:n9cbg3h2ie7enqpurmsg350lr3ata4nsjl(a)4ax.com... >> Does LTspice have a potentiometer component? > >Nope! From hearing Mike Engelhardt (the author) answer the question, I'm >pretty sure it's that way on purpose -- he really does prefer two resistors, >with one set to, e.g., {10k*x} and the other set to {10k*(1-x)}. (And then >you use a .param statement to have LTspice step through the various values of >x you're interested in.) > >I'm told that someone has posted (presumably on the Yahoo! group) a >potentiometer just bundling up the two resistors into a single package (as >Jim's .pdf demonstrates) in case you want something that looks "nicer." > >It's interesting that Mike seems to feel so strongly about pots one way >whereas John Warner of SIMetrix fame seems to like pots so much he added the >ability to use the cursor keys to "turn" the pot and automatically re-run >simulation each time! > I don't suppose that Linear Tech puts many pots on their chips. I'm still toying with a way to delay a signal 0 to 5 ns with one turn of a pot, without wrecking the bandwidth and eye diagram. Maybe it can't be reasonably done. John
From: John Popelish on 5 Oct 2007 13:56 John Larkin wrote: > I'm still toying with a way to delay a signal 0 to 5 ns with one turn > of a pot, without wrecking the bandwidth and eye diagram. Maybe it > can't be reasonably done. Does the pot adjust the clock frequency of a delay line?
From: John Larkin on 5 Oct 2007 15:44 On Fri, 05 Oct 2007 13:56:38 -0400, John Popelish <jpopelish(a)rica.net> wrote: >John Larkin wrote: > >> I'm still toying with a way to delay a signal 0 to 5 ns with one turn >> of a pot, without wrecking the bandwidth and eye diagram. Maybe it >> can't be reasonably done. > >Does the pot adjust the clock frequency of a delay line? No, that would be easy, but we want picosecond jitter and at least, say, 50 ps settability. I have seen LC delay lines that used varicaps instead of fixed caps, but that's really nasty. Base delay is big, delta-delay is small, impedance changes with delay, and tc's are rotten. The HP 8133A pulse generator does that, and it's a design worh studying, for its performance and sheer monstrosity. John
From: Helmut Sennewald on 5 Oct 2007 17:30 "Joel Kolstad" <JKolstad71HatesSpam(a)yahoo.com> schrieb im Newsbeitrag news:13gcqp98lamgo9a(a)corp.supernews.com... > "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in > message news:n9cbg3h2ie7enqpurmsg350lr3ata4nsjl(a)4ax.com... >> Does LTspice have a potentiometer component? > > Nope! From hearing Mike Engelhardt (the author) answer the question, I'm > pretty sure it's that way on purpose -- he really does prefer two > resistors, with one set to, e.g., {10k*x} and the other set to > {10k*(1-x)}. (And then you use a .param statement to have LTspice step > through the various values of x you're interested in.) > > I'm told that someone has posted (presumably on the Yahoo! group) a > potentiometer just bundling up the two resistors into a single package (as > Jim's .pdf demonstrates) in case you want something that looks "nicer." Hello, I have posted a few months ago a second type of pot into the Files section of the Yahoo group. The first pot has been controlled with a parameter while the latest example has a voltage controlled input. Membership is free! http://tech.groups.yahoo.com/group/LTspice/ Files > Lib > Potentiometer Best regards, Helmut > It's interesting that Mike seems to feel so strongly about pots one way > whereas John Warner of SIMetrix fame seems to like pots so much he added > the ability to use the cursor keys to "turn" the pot and automatically > re-run simulation each time! > > ---Joel
From: YD on 6 Oct 2007 10:44 Late at night, by candle light, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> penned this immortal opus: >Does LTspice have a potentiometer component? I'd like to do transient >analysis sweeps, as a function of pot rotation. > >I can't find this. Any other way to simulate the function? I really >need the varying resistances, so I can't just use a multiplier. > > >John http://tech.groups.yahoo.com/group/LTspice/files/%20Lib/Potentiometer/ - YD. -- Remove HAT if replying by mail.
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