cr_XD Posted June 5, 2004 Report Posted June 5, 2004 could anyone try the circuit in the link in the simulation software he uses and feedback what he sees in the osciloscope. i swear the output signal is smaller than the input signal, shouldn't it be the opposite or just look at the schematic and tell me where i've screwed up Quote
jefm Posted June 5, 2004 Report Posted June 5, 2004 To be honest...at a glance something looks a little off... I don't have any sim software...maybe I'll try to see what's catching my eye later... Quote
lovekraft Posted June 5, 2004 Report Posted June 5, 2004 You've got the battery wired backwards. Quote
cr_XD Posted June 5, 2004 Author Report Posted June 5, 2004 nope, i've tried it, the same problem, the reading in b is about half the reading in a. doesn't make sense to me. any other ideas?? edit: in the schematic i was trying to imitate it said +150V to that point, that is why i placed it like that. Quote
Saber Posted June 5, 2004 Report Posted June 5, 2004 The first thing that comes to mind is that the negative side of your battery is not connected to anything according to your drawing. It should go to ground. Quote
lovekraft Posted June 6, 2004 Report Posted June 6, 2004 With the circuit pictured with B+ at 150 volts, a 1 volt P/P sine wave in will give you approximately 30 volts P/P out into a 1Megohm load. Is that what you needed? Try adding a coupling cap in series with the output (.022uF or so) and a 1 Megohm resistor shunted to ground. If your o-scope input impedance is too low and there's no coupling cap, the operating point of the triode may be so low that it will clip almost immediately and lower the output level to nothing. Try it like this. It's more like a real gainstage, so it should give you a better idea of what you'll get in a real application. Connect your scope between the cap and the 1Meg load resistor. Quote
cr_XD Posted June 6, 2004 Author Report Posted June 6, 2004 no way to make it work i'm using electronics workbench multisim 7, any chances it could be the software. i would use spice, but i really don't know how to make it work Quote
lovekraft Posted June 6, 2004 Report Posted June 6, 2004 Did you add the cap and the load resistor? Without them, the simulator is trying to "guess" about ciruit conditions inside the o-scope. If that doesn't work, try the Circuitmaker Student package - it's limited, but it'll do tube preamps. Quote
cr_XD Posted June 6, 2004 Author Report Posted June 6, 2004 works great with that program . not so nice looking as electronics workbench tho Quote
lovekraft Posted June 7, 2004 Report Posted June 7, 2004 Yeah, it's like women or automobiles - some look really good, and some perform really well, but most don't manage to do both (especially for free). Or you can always spend $4K+ on MicroCap 8 Quote
cr_XD Posted June 7, 2004 Author Report Posted June 7, 2004 well, don't really need to perform that well if the look really good Quote
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