I don't remember if NPN worked or not, I'll try to test it tomorrow, I'm building a negative regulator. It's interesting how easy it is to get the negative voltage, same circuit, just move the negative feed, (ground) to the point between the inductor and the capacitor. A problem I have is the lack of higher voltage power supplies. I do have a Variac and I guess I could put a bridge on that. But that has no isolation. I got to see (hear) a 22uF 100V cap fail today, haven't found the canister and there was paper everywhere. I kind of think it got hot because of it's proximity to the 100 ohm resistors.
I just simmed the circuit with a NPN and it does run, (last attachment)
Since I'm always hands on with my power supply usage and it does have definite limit, I don't think I'm going to worry to much about current limits, If I find a need for it, I'll just use a LM317
I'm finished, for now anyway, the final screen shots were taken of 10 amp from Neg to Pos with no common, IRF4805 stayed cool, I could keep my finger on it after a minute's running, heat sink was cool also. My amp meters are a bit disappointing, as the vary and not real accurate, but I'm very happy with the rest of it. Especially because it stays cool as opposed to the heat it put out before just driving some LED light that I use on my bench, one has a LT1270 driving 4 10 watt LEDs in series, ~40 volts @ 1 amp, and the other is the 4 3 watt LEDs in series with NO limiting resistor that everyone says won't work, but it does, nicely!! (I'll add a photo of it tomorrow)
https://www.dropbox.com/sh/wfpkr5w0hcrz7a2/RoElm-fUVF
You're welcome, it was My pleasure,I have a variable power supply that had some problems, so i'm rebuilding it about the transformer is good for over 20 amps and 24 volts DC power supply. If you need to buy a power backup supply, i would just get a R9 270x, keep the parts already listed then add an SSD along with it if you can get a good deal on the rest of your parts.
Thanks for sharing with us.
Best Regards
Riello-ups
https://www.dropbox.com/sh/oir6ah6upe9jdyl/KuFYU3XU5EHi,
What is that oscillation picture about, is that the circuit too or a past circuit?
Also, it is not that an LED can not be driven from a voltage source. Of course i can connect an LED to a power supply, turn up the voltage slowly, and watch the LED current and see it light up nice and bright at 20ma if it is a small LED or 300ma if it is a high power LED. It's not that we can never do that.
What is is about is that if we leave the power supply set at the 3.5v (or whatever it comes out to for that LED) the LED characteristics may change over time with aging. This could also change while the LED is heating up. The LED's i have measured have a 2 to 3mv per degree C change in voltage with nearly constant current drive, so once they heat up they need a different voltage if they are to operated at the same current level. If the power supply output impedance is low enough, this means the LED either gets too much current or too little current after a while which makes the output dim somewhat. If it does not dim too much then we're ok but if not then we might not be happy with it.
Even a small series resistance can help with this that's why we like to do that too.
So it's not that it can never work like that, it's just that it is not as good as if it is done in a more reliable and consistent way.
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