Understanding electricity in the TPU.

[gyulasun]

Yes, I also thought of this schematic, after his text description.

I tried to correct as I think these P or N channel MOSFETs prefer getting DC polarities across their drain and source electrodes. Maybe they work in this particular setup with their drain-source electrodes mixed up, I never used them in reverse.  But if wattsup indeed mixed the electrodes up then the FETs body diodes were immediately get forward biased, when he switches on the 5V supply and those diodes effectively would short the drain source electrodes, regardless of the gate control voltage, so I am puzzled how they could have been controlled from the FG.  This is why I wrote, I can reflect on what I read as a circuit description.

Respectfully,  Gyula

[wattsup]

@GK and @gyulasun

I had described my connections correctly and thank you for your explanation which I followed also to realize the way I connected the PNP was in reverse so actually, when I removed the pulse to the PNP gate, it did not change anything, yes because of the internal diode. So now I connected them as you have recommended. Also, before I was sending the FG positive to both gates, now I am sending the FG positive to the NPN gate and the FG negative to the PNP gate. The life of an EE neophyte is not easy.

So now I go from the power supply positive, to the PNP source, PNP drain to the primary, other end of primary to the NPN drain and NPN source to power supply negative.

Amazingly the best results with this set-up is almost smack dab at the 5000hz. I totally freaked when I saw this.

Off the secondary, I figured out something very weird. My capacitor is a non-polarized motor starter type. So on one terminal I put one end of the secondary, on the other cap terminal I put three diodes with their other ends open so my other secondary wire can go to any one of them to see the differences in what the volt meter reads. The volt meter is right on the cap terminals.

Now when I put the secondary through a 1N5817 diode, I am getting AC up to 9 volts and on DC it reads around .08 with my LED bank lit up. When I remove the LED the voltage rises to around 15 volts AC.

When I put the secondary through a 1N4984 diode, I am getting DC about 8 volts and on the AC it read around .6 volts with my LED lit up. When I remove the LED the voltage rises to around 14 volts DC.

I will have to make a video on this, but I want to test a few more things.

What if I go PNP to an outer ring to primary toroid to another outer ring then to NPN. Those outer rings would be on the input and output of the primary toroid being pulsed at the same time and if there is any AC happening, this would produce ring fields in two directions. I would like to see how another coil over the rings would react to this. I will try this tonight. More to come.

Added:

Oh yeh, last night I connected the secondary output to the cathode of a 6X8 vacuum tube and it lit up. This tube however has the wrong specs that I need so I will look for another one in my box of tubes and try it out, then measure voltage off the plate.

[gyulasun]

....
I had described my connections correctly and thank you for your explanation which I followed also to realize the way I connected the PNP was in reverse so actually, when I removed the pulse to the PNP gate, it did not change anything, yes because of the internal diode. So now I connected them as you have recommended. Also, before I was sending the FG positive to both gates, now I am sending the FG positive to the NPN gate and the FG negative to the PNP gate. The life of an EE neophyte is not easy.
So now I go from the power supply positive, to the PNP source, PNP drain to the primary, other end of primary to the NPN drain and NPN source to power supply negative.
...

Ok wattsup, now what I do not get is why you connect the FG negative to the gate electrode of the N channel MOSFET?
Do you find significant difference between:
connecting the FG negative to the power supply negative and the two gates of the MOSFETs are connected together   OR
as you wrote the FG negative goes to the gate of the N channel MOSFET?

I think the preferred method would be the FG negative i.e. the zero ground point of the FG would be tied to the negative pole of the power supply.

One would think there is a difference in the switch on and mainly the switch off times of the p and n channel MOSFETs... that could play any  role in the switching actions?  It is sure there is a difference in their reaction time.

rgds,  Gyula

[wattsup]

Hi @gyulasun;

Well what I indicated is the positive of the FG is going to the gate of the NPN or N-Channel mosfet and the negative of the FG is going to the PNP gate or the P-Channel mosfet. I think you may have understood that in reverse.

The reason I am (was) doing this is mainly due to how I understand the specs on these two mosfets (IRF840 and IRF9540). The PNP IRF9540 specs, when I look at the Gate to Threshold Voltage says minimum -2 to maximum -4 volts. So I thought the gate of the PNP needs only a negative voltage source. On the NPN IRF840 the same spec says +2 minimum to +4 maximum. So this is why I connected the FG in that way.

But to tell you the real fact is that I do not really understand the specs but just the rudimentary overall usage, which can be wrong in any or every case. But this has never stopped me from doing tests and observing effects.

One of the problems I have is when you say to put the negative of the FG with the negative of the power supply. I had been pulsing mosfets with only the positive of the FG and it has worked in the past so this is why I never used it. OK I will do as you say.

OK, I did as you say. I made some other minor changes too and the AC and DC effect is no longer there. Only DC output. But I found some great results.

I made a video of the current set-up as shown by @GK diagram, simply because I am getting very good voltage output that I have never seen before. The video is located here.

The video is located here;
http://www.youtube.com/watch?v=jfhbeNFJM5s

If there is one thing I would like to tell other TPU researchers that have circuits with one or more diodes, YOU HAVE TO TRY THE CIRCUIT WITH SEVERAL DIODE TYPES. In my last tests, if I only used the same diode all the time, I would never see these results. You could think the circuit you made is not working as you want, but just changing the diode can make all the difference.

I will reproduce the AC/DC effect again using different diodes and make another video during the week.

In this video when I increase the applied power supply voltage, the output voltage was increasing proportionally meaning that this is perfect for a device that would have to run with gain.

wattsup

[gyulasun]

Hi @gyulasun;

Well what I indicated is the positive of the FG is going to the gate of the NPN or N-Channel mosfet and the negative of the FG is going to the PNP gate or the P-Channel mosfet. I think you may have understood that in reverse.

hi Wattsup,

Yes, I mistyped it, sorry for that.

The reason I am (was) doing this is mainly due to how I understand the specs on these two mosfets (IRF840 and IRF9540). The PNP IRF9540 specs, when I look at the Gate to Threshold Voltage says minimum -2 to maximum -4 volts. So I thought the gate of the PNP needs only a negative voltage source. On the NPN IRF840 the same spec says +2 minimum to +4 maximum. So this is why I connected the FG in that way. 

I see. Normally when you use a voltage source (battery, mains, generator) then you always consider two poles (when it is DC) or two points (when it is AC) between which you understand the amplitude info of the voltage source like a 9V battery or 120V mains voltage etc.  You always measure voltage between two points, not one point in itself, right? 
This is so with the gate voltage in case of MOSFETs, they do not state in every point of the data sheet that it is meant between the gate AND the source electrodes or with respect to the source electrode of the MOSFET BUT they mean it! Gate threshold voltage is always meant with respect to the source electrode of a FET. And in the data sheet there are Figures showing recommended measurements setups how they mean a specific data.

One of the problems I have is when you say to put the negative of the FG with the negative of the power supply. I had been pulsing mosfets with only the positive of the FG and it has worked in the past so this is why I never used it. OK I will do as you say. 

Thanks. It can work with only the positive of the FG but two things are involved with it: it may work erraticly and you will not have any idea of something happened due to the circuit properties or due to an erratic MOSFET switch on or off (for instance the gate-source self capacitance has no possibility to discharge correctly because the gate is floating with respect to the source electrode), the other thing is you may also input spurious frequencies you are also not aware of, (the gate electrode has a MegaOhm input impedance at low frequencies like 50 or 60Hz mains and you always have field strength from the mains in a room or lab etc that can modulate the input frequency coming from the FG.
It is true an FG has a low output impedance (pure 50 Ohm) but if you use a ground independent circuit with a battery as the voltage source (not a power supply fed from the mains like the FG) then chances are the gate is still unterminated (it cannot 'see' fully the FG's output) so it can remain at high impedance, hence can pick up 'waves' as 'foreign' voltages and you may not be aware of it.

If you used only the positive output of the FG so far for driving mainly N channel MOSFETs and you found your MOSFET was switching as you expected then probably you used power supply as the DC voltage source to feed the drain-source electrodes, hence chances were the negative supply point was enough 'low impedance' point via the mains network from the FG's negative output or vice versa so the gate-source path had good chance for normal operation. Not so in case of operating from a battery, then the path for the low impedance route is missing via the mains network, unless some other measuring instrument's (scope etc) negative point brings it to the source electrode of the MOSFET or JFET.

If you study any schematic that includes a MOSFET or JFET you find that the gate-source electrodes always have a DC path between them: either a resistor or a coil or a transformer's coil, these DC conducting components insure the gate-source capacitance can discharge (the RC time constant is important of course).  If the DC path is missing (and it can be missing if you use only the FG's positive output), then the control of the gate may become erratic.  See for instance Groundloop's schematic for the two coil switch shown earlier, the 2 kOhm resistors are between the gate-source electrodes. (In case of using an NE555 timer for controlling a MOSFET directly, the DC path between the gate-source is insured by the 555's inner circuits but then you have to connect the 555 negative supply point with the N channel MOSFET's source electrode too, right?

OK, I did as you say. I made some other minor changes too and the AC and DC effect is no longer there. Only DC output. But I found some great results.

Thanks for showing the video, nice job.  I cannot judge if "the AC and DC effect is no longer there"  result is good or bad but it is ok you found some great results.  One thing is sure: if you apply correct methods for serving the MOSFETs (or any other device) then the MOSFETs will operate as they are destined to and you can depend on their performance and focus on the effect of the now correct switching.

RE on your finding the different diodes behaviour:  the so called reverse recovery time is the important data here for them, t_rr, and there are big differences between the types of course.  So called fast or extra/super fast recovery diodes are preferred for capturing voltage spikes from the collapsing magnetic fields, t_rr should be in the 20-30 nanosecond range or even better.

rgds,  Gyula