LTSpice query

Greetings, gentlemen,

The image below is how I've been representing variable resistors in LTS for like ever. But this circuit fragment - because it contains a disproportionately large number of variable resistors compared to everything else- really forced me to face up to the issue that I'm doing something wrong here. There must surely be a more elegant way than making up v.res out of two fixed resistors and tapping the node between them for the wiper?

formatting link

--

"When constituencies are small their elected representatives must concern themselves with the local interests of their constituents. When political representatives are distant and faceless, on the other hand, and represent vast numbers of unknown constituents, they represent not their constituents, but special interest groups whose lobbyists are numerous and ever present. Typically in Europe a technocrat is an ex-politician or a civil servant. He is unelected, virtually impossible to dislodge during his term of employment and has been granted extensive executive and even legislative power without popular mandate and without being directly answerable to the people whose interests he falsely purports to represent."

- Sir James Goldsmith (Member of the European Parliament) 1933 - 1997

Reply to
Cursitor Doom
Loading thread data ...

Too dinky to see properly; try some other way (eg: LT Spice listing).

Reply to
Robert Baer

"ExpressPCB Netlist" "LTspice IV Version 4.23l"

1 0 0 "" "" "" "Part IDs Table" "V1" "20" "" "V2" "10" "" "R1" "500" "" "R2" "500" "" "R3" "3850" "" "R4" "2500" "" "R5" "19.6k" "" "D1" "MBR0520L" "" "R6" "2500" "" "R7" "2500" "" "R8" "2500" "" "R9" "46.4k" "" "R10" "6810" "" "R11" "1470" ""

"Net Names Table" "N001" 1 "0" 3 "N005" 9 "N002" 12 "N003" 16 "N004" 18 "Vref" 21 "N007" 23 "N006" 26

"Net Connections Table"

1 1 1 2 1 5 1 0 2 1 2 4 2 2 1 5 2 3 1 6 2 9 2 7 2 10 1 8 2 14 2 0 3 2 2 10 3 4 2 11 3 11 2 0 4 3 2 13 4 4 1 14 4 5 2 15 4 8 2 0 5 6 1 17 5 8 1 0 6 6 2 19 6 9 1 20 6 12 2 0 7 7 1 22 7 12 1 0 8 7 2 24 8 13 1 25 8 14 1 0 9 10 2 27 9 11 1 28 9 13 2 0
--

"The BEST Deal is NO DEAL"
Reply to
Cursitor Doom

Well, i imported the above as a file into ExpressPCB with no complaints after deleting the last line "--" and saw nothing. And what does LTSpice have to do with ExpressPCB?

Reply to
Robert Baer

No idea at all. ISTR I have the same trouble every time I try to post an LT spice diagram. Some kind soul has to come along and remind me where to find the correct thing to select under which tab in order to do it. Perhaps I'll try to upload the schematic again; blow it up a bit more this time.....

--

"The BEST Deal is NO DEAL"
Reply to
Cursitor Doom

Okay, I've blown the original image up somewhat. See if this is any more readable:

formatting link

--

"The BEST Deal is NO DEAL"
Reply to
Cursitor Doom

Reply to
Robert Baer

Unfortunately that attachment didn't resolve at this end. Could you possibly please just c+p the plain text as a message body?

--

"The BEST Deal is NO DEAL"
Reply to
Cursitor Doom

Cursitor Doom wrote:

notch.asc

Version 4 SHEET 1 5945676 13421556 WIRE 1776 -496 1648 -496 WIRE 2192 -496 1776 -496 WIRE 2608 -496 2192 -496 WIRE 3024 -496 2608 -496 WIRE 1648 -480 1648 -496 WIRE 1776 -432 1776 -496 WIRE 1888 -432 1776 -432 WIRE 2096 -432 1968 -432 WIRE 2128 -432 2096 -432 WIRE 2192 -432 2192 -496 WIRE 2304 -432 2192 -432 WIRE 2512 -432 2384 -432 WIRE 2544 -432 2512 -432 WIRE 2608 -432 2608 -496 WIRE 2704 -432 2608 -432 WIRE 2896 -432 2784 -432 WIRE 2928 -432 2896 -432 WIRE 3024 -432 3024 -496 WIRE 3136 -432 3024 -432 WIRE 3344 -432 3216 -432 WIRE 3376 -432 3344 -432 WIRE 1776 -416 1776 -432 WIRE 2096 -416 2096 -432 WIRE 2192 -416 2192 -432 WIRE 2512 -416 2512 -432 WIRE 2608 -416 2608 -432 WIRE 2896 -416 2896 -432 WIRE 3024 -416 3024 -432 WIRE 3344 -416 3344 -432 WIRE 1648 -368 1648 -400 WIRE 1776 -320 1776 -352 WIRE 1904 -320 1776 -320 WIRE 2096 -320 2096 -352 WIRE 2096 -320 1968 -320 WIRE 2192 -320 2192 -352 WIRE 2320 -320 2192 -320 WIRE 2512 -320 2512 -352 WIRE 2512 -320 2384 -320 WIRE 2608 -320 2608 -352 WIRE 2720 -320 2608 -320 WIRE 2896 -320 2896 -352 WIRE 2896 -320 2784 -320 WIRE 3024 -320 3024 -352 WIRE 3152 -320 3024 -320 WIRE 3344 -320 3344 -352 WIRE 3344 -320 3216 -320 WIRE 1776 -240 1776 -320 WIRE 1808 -240 1776 -240 WIRE 1936 -240 1888 -240 WIRE 1984 -240 1936 -240 WIRE 2096 -240 2096 -320 WIRE 2096 -240 2064 -240 WIRE 2192 -240 2192 -320 WIRE 2224 -240 2192 -240 WIRE 2352 -240 2304 -240 WIRE 2400 -240 2352 -240 WIRE 2512 -240 2512 -320 WIRE 2512 -240 2480 -240 WIRE 2608 -240 2608 -320 WIRE 2640 -240 2608 -240 WIRE 2752 -240 2720 -240 WIRE 2784 -240 2752 -240 WIRE 2896 -240 2896 -320 WIRE 2896 -240 2864 -240 WIRE 3024 -240 3024 -320 WIRE 3040 -240 3024 -240 WIRE 3184 -240 3120 -240 WIRE 3232 -240 3184 -240 WIRE 3344 -240 3344 -320 WIRE 3344 -240 3312 -240 WIRE 1936 -192 1936 -240 WIRE 2352 -192 2352 -240 WIRE 2752 -192 2752 -240 WIRE 3184 -192 3184 -240 FLAG 1648 -368 0 FLAG 1936 -192 0 FLAG 2128 -432 W FLAG 2352 -192 0 FLAG 2544 -432 X FLAG 2752 -192 0 FLAG 2928 -432 Y FLAG 3184 -192 0 FLAG 3376 -432 Z SYMBOL voltage 1648 -496 R0 SYMATTR InstName V1 SYMATTR Value AC 1. SYMBOL res 1984 -448 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value {6*R} SYMBOL cap 2080 -416 R0 SYMATTR InstName C2 SYMATTR Value {C} SYMBOL cap 1760 -416 R0 SYMATTR InstName C1 SYMATTR Value {C} SYMBOL cap 1968 -336 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value {C} SYMBOL res 1904 -256 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value {w*R} SYMBOL res 2080 -256 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value {(1-w)*R} SYMBOL res 2400 -448 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value {6*R} SYMBOL cap 2176 -416 R0 SYMATTR InstName C4 SYMATTR Value {C} SYMBOL cap 2496 -416 R0 SYMATTR InstName C5 SYMATTR Value {C} SYMBOL cap 2384 -336 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C6 SYMATTR Value {C} SYMBOL res 2320 -256 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R5 SYMATTR Value {x*R} SYMBOL res 2496 -256 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R6 SYMATTR Value {(1-x)*R} SYMBOL res 2800 -448 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R7 SYMATTR Value {6*R} SYMBOL cap 2592 -416 R0 SYMATTR InstName C7 SYMATTR Value {C} SYMBOL cap 2880 -416 R0 SYMATTR InstName C8 SYMATTR Value {C} SYMBOL cap 2784 -336 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C9 SYMATTR Value {C} SYMBOL res 2736 -256 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R8 SYMATTR Value {y*R} SYMBOL res 2880 -256 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value {(1-y)*R} SYMBOL res 3232 -448 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R10 SYMATTR Value {6*R} SYMBOL cap 3008 -416 R0 SYMATTR InstName C10 SYMATTR Value {C} SYMBOL cap 3328 -416 R0 SYMATTR InstName C11 SYMATTR Value {C} SYMBOL cap 3216 -336 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C12 SYMATTR Value {C} SYMBOL res 3136 -256 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R11 SYMATTR Value {z*R} SYMBOL res 3328 -256 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R12 SYMATTR Value {(1-z)*R} TEXT 2976 -144 Left 2 !.ac oct 500 100 10k

TEXT 2456 -512 Bottom 2 ;From Horowitz and Hill, The Art of Electronics,

2nd Ed, Cambridge, p. 281 TEXT 2288 -144 Left 2 !.params w=.0005 x=.005 y=.05 z=.5 TEXT 2416 -104 Top 1 ;This example schematic is supplied for informational/educational purposes only.
Reply to
Robert Baer
[...]

Ah, I see now; thanks, Robert. An obvious improvement for sure, but still could be better IMHO. Hopefully Mike E will read this at some point and set about the task! :)

--

"The BEST Deal is NO DEAL"
Reply to
Cursitor Doom

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.