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Temperature compensation in LTSpice?

Started by Bill Bowden February 14, 2013
Is it possible to simulate circuit performance using LTSpice under
different temperature conditions? Say you have a single NPN transistor
with grounded emitter and a collector load and a resistor from base to
collector so the collector voltage is about half the supply voltage. I
understand the result would depend on the HFE of the transistor,
temperature, and maybe not very stable. Just wondering if LTSpice can
provide any interesting information for some particular transistor. DC
voltage change verses temperature.

-Bill

On Thu, 14 Feb 2013 18:45:56 -0800 (PST), Bill Bowden
<bperryb@bowdenshobbycircuits.info> wrote:

>Is it possible to simulate circuit performance using LTSpice under >different temperature conditions? Say you have a single NPN transistor >with grounded emitter and a collector load and a resistor from base to >collector so the collector voltage is about half the supply voltage. I >understand the result would depend on the HFE of the transistor, >temperature, and maybe not very stable. Just wondering if LTSpice can >provide any interesting information for some particular transistor. DC >voltage change verses temperature. > >-Bill
Here's a simple temperature sweep example: https://dl.dropbox.com/u/53724080/Circuits/TC_diode_sweep.asc -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
On Feb 14, 11:11=A0pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Thu, 14 Feb 2013 18:45:56 -0800 (PST), Bill Bowden > > <bper...@bowdenshobbycircuits.info> wrote: > >Is it possible to simulate circuit performance using LTSpice under > >different temperature conditions? Say you have a single NPN transistor > >with grounded emitter and a collector load and a resistor from base to > >collector so the collector voltage is about half the supply voltage. I > >understand the result would depend on the HFE of the transistor, > >temperature, and maybe not very stable. Just wondering if LTSpice can > >provide any interesting information for some particular transistor. DC > >voltage change verses temperature. > > >-Bill > > Here's a simple temperature sweep example: > > https://dl.dropbox.com/u/53724080/Circuits/TC_diode_sweep.asc
Hey dropbox is pretty cool! (I need to investigate) George H.
> > -- > > John Larkin =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Highland Technology Incwww=
.highlandtechnology.com=A0 jlarkin at highlandtechnology dot com
> > Precision electronic instrumentation > Picosecond-resolution Digital Delay and Pulse generators > Custom timing and laser controllers > Photonics and fiberoptic TTL data links > VME =A0analog, thermocouple, LVDT, synchro, tachometer > Multichannel arbitrary waveform generators
On Fri, 15 Feb 2013 05:53:43 -0800 (PST), George Herold <gherold@teachspin.com>
wrote:

>On Feb 14, 11:11&#2013266080;pm, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> On Thu, 14 Feb 2013 18:45:56 -0800 (PST), Bill Bowden >> >> <bper...@bowdenshobbycircuits.info> wrote: >> >Is it possible to simulate circuit performance using LTSpice under >> >different temperature conditions? Say you have a single NPN transistor >> >with grounded emitter and a collector load and a resistor from base to >> >collector so the collector voltage is about half the supply voltage. I >> >understand the result would depend on the HFE of the transistor, >> >temperature, and maybe not very stable. Just wondering if LTSpice can >> >provide any interesting information for some particular transistor. DC >> >voltage change verses temperature. >> >> >-Bill >> >> Here's a simple temperature sweep example: >> >> https://dl.dropbox.com/u/53724080/Circuits/TC_diode_sweep.asc > >Hey dropbox is pretty cool! (I need to investigate)
Dropbox is fabulous. The same files appear on all your PCs, anywhere. I use it for my mountain cabin automation system, as a painless and reliable way to share files in real time. And for work+home projects: no more flash sticks! I use it for sharing big files with my clients, too. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
On Feb 14, 8:11=A0pm, John Larkin

<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Thu, 14 Feb 2013 18:45:56 -0800 (PST), Bill Bowden > > <bper...@bowdenshobbycircuits.info> wrote: > >Is it possible to simulate circuit performance using LTSpice under > >different temperature conditions? Say you have a single NPN transistor > >with grounded emitter and a collector load and a resistor from base to > >collector so the collector voltage is about half the supply voltage. I > >understand the result would depend on the HFE of the transistor, > >temperature, and maybe not very stable. Just wondering if LTSpice can > >provide any interesting information for some particular transistor. DC > >voltage change verses temperature. > > >-Bill >
> Here's a simple temperature sweep example: > > https://dl.dropbox.com/u/53724080/Circuits/TC_diode_sweep.asc >
Yes, that works fine to plot the e/b and b/c voltage temp conditions. I tried adding a spice directive of (.step temp 0 50 5) to my transistor stage and I get 10 lines displayed (5 to 6 volts) which I presume correspond to the 10 temperature steps. But the display doesn't indicate what voltage occurs at what temperature. How to fix that? -Bill Version 4 SHEET 1 880 680 WIRE 144 16 16 16 WIRE -128 144 -192 144 WIRE 16 144 16 96 WIRE 16 144 -64 144 WIRE 16 208 16 144 WIRE -192 256 -192 144 WIRE -160 256 -192 256 WIRE -48 256 -80 256 WIRE 16 320 16 304 FLAG 144 96 0 FLAG 16 320 0 SYMBOL voltage 144 0 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value 12 SYMBOL npn -48 208 R0 SYMATTR InstName Q2 SYMATTR Value 2N3904 SYMBOL res 0 0 R0 SYMATTR InstName R3 SYMATTR Value 22k SYMBOL res -64 240 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R4 SYMATTR Value 5000k SYMBOL diode -64 128 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 36 -4 VTop 0 SYMATTR InstName D2 SYMATTR Value 1N4148 TEXT -40 392 Left 0 !.step temp 0 50 5 TEXT -200 392 Left 0 !.tran .1s
On Fri, 15 Feb 2013 21:01:57 -0800, Bill Bowden wrote:

> But the display doesn't indicate > what voltage occurs at what temperature. How to fix that?
Right click on the plot screen. Click on "Select Steps" -- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)