Pspice perpetual motion machine

[broli]

If you're feeding it back should it not show an exponential growth since it looks linear now. And man good luck on finding people who want to read your textual diagram  .  What is the problem in posting a screencap of the diagram from the program?

[sandor]

More screenshots here.

There IS no circuit diagram from the program, there is only the text description you see in the first post. That is what the software reads and it doesn't generate a pictorial schematic. I think it's pretty easy to understand myself, enough so that I didn't even bother to even write down the schematic, I just typed it up.

It APPEARS linear because the exponential behavior is only just starting. Look at the y axis. This is only from 72.4 to 73.6 volts and that's only a percent and a half increase in voltage. You'd have to simulate it for a much longer period of time for it to look like e^x instead of a linear increase.

Also it would not keep up exponential increase forever. Remember a fixed current is being fed into the base of the transistor on the voltage pulses that drive the device and the increase will only continue until you get to the point where the current in the transistor hits the gain of the transistor times this base current.

[sandor]

I also picked a load of such a value that it WOULDN'T increase very fast. If the load resistance was a little higher it would go up much faster, maybe not just a percent and a half in this time period but 10 or 20% for just twice the load resistance. And if the load resistance was a bit lower the voltage would decrease, and presumably there's some value where it would be pseudostable.

[broli]

Here's a way to make a diagram "quickly".

http://www.falstad.com/circuit/

Btw i'm not an EE I only have some basic electrical knowledge. But I want to help you make this as clear as possible to other people  .

[sandor]

Well, it didn't like it, in part probably because it wouldn't let me set the coupling coefficient of the transformer (it should be .965 - because that's what I measured with the ferrite cores I owned). But here's the picture. Missing from the picture because it wouldn't display it, is the supply voltage of 170 volts DC, the duty cycle of the signal to the base of the transistor being 25% (it wouldn't let me set that either, I suspect it's just a brief pulse), and the transformer's coil's inductances. The one connected to the load is 72 microhenries and the one connected in series with the 1 uF capacitor is 200 microhenries, which by the way, puts their turns ratio at 3 to 5 since 3 squared divided by 5 squared is .36=72/200. I have left off the parasitic series resistances that go along with the inductors but aside from that it is 45.cir, the 627% efficient one - Is it clear now?