LTSpice triode model
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Posted by Andrew Holme on November 26, 2008, 4:04 pm
Please log in for more thread options http://www.duncanamps.com/spice/valves/dmtriodep.inc The LTSpice .asc file below shows anode current when Vgc < -80V. Do valves do this, or is it a bug in the model? What's the fix? Version 4 SHEET 1 2020 680 WIRE 928 176 832 176 WIRE 928 192 928 176 WIRE 832 288 832 176 WIRE 928 288 928 272 WIRE 928 336 880 336 WIRE 928 368 928 336 WIRE 864 464 864 384 WIRE 928 464 928 448 FLAG 928 288 0 FLAG 928 464 0 FLAG 864 464 0 SYMBOL voltage 928 176 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName Va SYMATTR Value 150 SYMBOL Misc\triode 832 336 M0 SYMATTR InstName U1 SYMATTR Value NH12AU7 SYMATTR SpiceModel NH12AU7 SYMBOL voltage 928 352 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName Vgc SYMATTR Value "" TEXT 1040 288 Left 0 !.include dmtriodep.inc TEXT 1040 368 Left 0 !.dc Vgc -150 0 | ||||||||||||||||||||||||||||
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Posted by Fred on November 26, 2008, 4:38 pm
Please log in for more thread options Basically there are two kinds of triode models, the Leach and the Koren. I favor the Koren models. I have found them to be reasonably accurate if you stay within normal operating parameters. Get too far away from that and the models get quirky. Best regards, Fred | ||||||||||||||||||||||||||||
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Posted by Tim Williams on November 26, 2008, 5:53 pm
Please log in for more thread options >I found these triode models:
> > http://www.duncanamps.com/spice/valves/dmtriodep.inc > > The LTSpice .asc file below shows anode current when Vgc < -80V. Do > valves do this, or is it a bug in the model? What's the fix? I don't know (or care ;-) ) much about SPICE, but I know plenty about 12AU7. If plate voltage is over 1kV or so, I might expect to see some current at -80Vg. At any plate voltage, there will be some leakage, which should be much less than a miliampere, especially at -80Vg. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms | ||||||||||||||||||||||||||||
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Posted by Andrew Holme on November 26, 2008, 6:11 pm
Please log in for more thread options
>>I found these triode models:
>> >> http://www.duncanamps.com/spice/valves/dmtriodep.inc >> >> The LTSpice .asc file below shows anode current when Vgc < -80V. Do >> valves do this, or is it a bug in the model? What's the fix? >
> I don't know (or care ;-) ) much about SPICE, but I know plenty about > 12AU7. If plate voltage is over 1kV or so, I might expect to see some > current at -80Vg. At any plate voltage, there will be some leakage, which > should be much less than a miliampere, especially at -80Vg. The above model is very wrong at Vg < -80V. I've just found a better one on the same website: http://www.duncanamps.com/spicevalvest.html#12AU7A | ||||||||||||||||||||||||||||
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Posted by Andrew Holme on November 26, 2008, 6:45 pm
Please log in for more thread options
>
>>>I found these triode models:
>>> >>> http://www.duncanamps.com/spice/valves/dmtriodep.inc >>> >>> The LTSpice .asc file below shows anode current when Vgc < -80V. Do >>> valves do this, or is it a bug in the model? What's the fix? >>
>> I don't know (or care ;-) ) much about SPICE, but I know plenty about >> 12AU7. If plate voltage is over 1kV or so, I might expect to see some >> current at -80Vg. At any plate voltage, there will be some leakage, >> which should be much less than a miliampere, especially at -80Vg. >
> The above model is very wrong at Vg < -80V. > > I've just found a better one on the same website: > > http://www.duncanamps.com/spicevalvest.html#12AU7A Better in one way, worse in another :( This manages to suck 22.8mA through a 68K anode load resistor from a 150V supply, giving an anode voltage of -1.4KV. | ||||||||||||||||||||||||||||
>
> http://www.duncanamps.com/spice/valves/dmtriodep.inc
>
> The LTSpice .asc file below shows anode current when Vgc < -80V. Do valves
> do this, or is it a bug in the model? What's the fix?
>
> Version 4
> SHEET 1 2020 680
> WIRE 928 176 832 176
> WIRE 928 192 928 176
> WIRE 832 288 832 176
> WIRE 928 288 928 272
> WIRE 928 336 880 336
> WIRE 928 368 928 336
> WIRE 864 464 864 384
> WIRE 928 464 928 448
> FLAG 928 288 0
> FLAG 928 464 0
> FLAG 864 464 0
> SYMBOL voltage 928 176 R0
> WINDOW 123 0 0 Left 0
> WINDOW 39 0 0 Left 0
> SYMATTR InstName Va
> SYMATTR Value 150
> SYMBOL Misc\triode 832 336 M0
> SYMATTR InstName U1
> SYMATTR Value NH12AU7
> SYMATTR SpiceModel NH12AU7
> SYMBOL voltage 928 352 R0
> WINDOW 123 0 0 Left 0
> WINDOW 39 0 0 Left 0
> SYMATTR InstName Vgc
> SYMATTR Value ""
> TEXT 1040 288 Left 0 !.include dmtriodep.inc
> TEXT 1040 368 Left 0 !.dc Vgc -150 0