Donald Smith Devices too good to be true

[janost]

im studying to put my mind inside this and
the switch connections are kind of a mystery to me, but could be the funtion of the transistors you see K monitoring in vids, or representing a spark event?

The switches are HV-switches, aka sparkgaps.

A sparkgap, Neon, CFL or mosfet is a very high impendance when not conducting.
Like an open switch.

[Gedfire]

Donald Smith Tower Device

Hello All,

Thanks for the splendid lessons on Capacitor Charging so far.


I spent some time analysing the pics by soundiceuk and Dons Videos.My target, the Tower Device.The one with the unusual transformer from India.There seem to be 2 versions.Tall and Short.

Here is the challenge: Can we identify the components and how they are connected. Having examined the MetaCafe Video and the 2005 series plus the all new pics from Soundiceuk, I think I may have identified the components (apart from the really obvious ones) and how the whole thing is wired.

But I could be wrong.For example,I am thinking that he is using a battery charger and some form of signal generator/power supply with variable frequency,voltage and amps to power the 50 Farad cap.

How is he doing that.The battery is obvious.So is the capacitor, what exactly are the other stuff as shown in soundiceuk pics.Car battery charger? Its in red! Cant see the words, but its UL certified

Next to it is what appears to be a signal gen or capacitance/dielectric tester or PSU.Also Don would have to use mostly off the shelve approved stuff as he would have had a hard time with the haters to get his original stuff certified it seems.

In DVD1 part 1 we see battery,capacitor and what seems to be an inverter.The only thing visible to me on what appears to be the inverter is 600.600 what?


The middle portion of the taller tower appears to be just an extra large inverter which connects to the transformer in the last or lower third.

The shorter tower does not have this inverter section.


Again,I have hypothesised how the tower is wired but, just not sure yet.

Any thoughts.I will reveal 1 more detailed that many may have missed later.



Ged

[Gedfire]

Sharing Donald Files

Hi All,


Unfortunately, I have not gotten any links from anyone who has the good stuff that soundiceuk offered on Donald Smith pics, documents,. anyone.... even a page come on....!

I am a Don junkie here....

Ged

[Dave45]

Scroll

[janost]

Scroll

What is that..thing?

[janost]

What I'm planning to do is Tesla style:
Charge a cap from the secondary and fire it into a coil.

At 300v a sparkgap is not going to work.
A neonbulb wont sustain the current when it fires.

So what is left?
A mosfet? An SCR, like in a capacitor discharge ignition?

I have mosfets that can handle 900v and SCRs that handle a 1000v, no problem.
And the will literaly short the charged capacitor to the coil.

What is the function of the reversed diod in a power mosfet?
Will it conduct reverse current from some volts or?

[level]

What I'm planning to do is Tesla style:
Charge a cap from the secondary and fire it into a coil.

At 300v a sparkgap is not going to work.
A neonbulb wont sustain the current when it fires.

So what is left?
A mosfet? An SCR, like in a capacitor discharge ignition?

I have mosfets that can handle 900v and SCRs that handle a 1000v, no problem.
And the will literaly short the charged capacitor to the coil.

What is the function of the reversed diod in a power mosfet?
Will it conduct reverse current from some volts or?

Have a look at SIDAC's. They will fire like a sparkgap or GDT when their threshold voltage is reached (you can get them with voltage thresholds in the 300V range I believe). Check the specs of the SIDAC to see what its on resistance is. I think SIDAC's have a negative resistance characteristic , i.e., once they fire their current increases even though the voltage across them is falling. The one drawback of a SIDAC is that it will continue to conduct until the current falls below its minimum current threshold, and then it will shut off. If you don't care about a fast and sharp cutoff, then a SIDAC just might work well for you...

P.S. The built in reverse diode in power Mosfets is to help protect the Mosfet from high voltage reverse voltage spikes.

[mainsen]

Hey,
no transformer, just Tesla Coil driven by Kacher (no ground connection), and 1 diode from top (where normal the TC sparks are) to spark gap and caps (so 1 wire only, anode at TC side), ground connection on other side of spark gap and caps (this is only ground connection in the setup)

thats great to hear
and you may have better luck with even smaller capacitance, i've gotten good results with 5 and 10 nf, it just depends on your particular transformer output. and yeah id start with matching the bulb to input power as you did, then add double the bulbs and see what you needed to change to get them fully lit. if you dont see for example 50 watts brightness, for 30 watts input... then i recommend using a regular full size NST having a center tap to case/ground

And i found it is necesary to ground the transformer as well, so i could be wrong with single ended trafo's but center tapped trafo's will work just like mine did
also, due to using the cap on output as i have the schem, best to use DC bulbs not AC, but you will still get some effect

just curious, did you use both ends of transformer output to 2 diodes coming together, and ground for neg side?

[janost]

P.S. The built in reverse diode in power Mosfets is to help protect the Mosfet from high voltage reverse voltage spikes.

Yes, but will it conduct reverse current and not break down?

Yes, I'll have a look at SIDACs.
That it wont shutdown until zero current is like an SCR, right?

[janost]

I did a checkup on SIDACs and I like it

They are like a semiconductor version of a sparkgap.
Just what I need.

[level]

Yes, but will it conduct reverse current and not break down?

Hi janost. I am not quite sure what you are asking. It will work just like if you connected an external diode from the Source to the Drain to protect the Drain-Source junction from negative voltage spikes, if that helps any.

Yes, but will it conduct reverse current and not break down?
Yes, I'll have a look at SIDACs.
That it wont shutdown until zero current is like an SCR, right?

It is similar, except it does not shut off when reaching a voltage zero crossing point, but shuts off when the current falls below its minimum holding current.
SIDAC's and DIAC's

[janost]

Hi janost. I am not quite sure what you are asking. It will work just like if you connected an external diode from the Source to the Drain to protect the Drain-Source junction from negative voltage spikes, if that helps any.



It is similar, except it does not shut off when reaching a voltage zero crossing point, but shuts off when the current falls below its minimum holding current.
SIDAC's and DIAC's

If I fire a cap with a mosfet into a coil, there will be oscillations and reverse current over the mosfet.
Can I do without an external diode?
What I'm asking, is it good for a flyback diode?

So the DIAC/SIDAC will hold until the current drops below a minimum holding current (like an SCR) and with my external reverse diode would be after the first halfcycle?

[level]

If I fire a cap with a mosfet into a coil, there will be oscillations and reverse current over the mosfet.
Can I do without an external diode?

You can do without the diode if you will not ever have reverse voltage peaks that might exceed the maximum reverse voltage rating for the mosfet.

So the DIAC/SIDAC will hold until the current drops below a minimum holding current (like an SCR) and with my external reverse diode would be after the first halfcycle?

Yeah, sorry, the minimum holding current shut off works similar to an SCR.
Not sure what you mean about the diode in relation to the SIDACs. I thought we were talking about the reverse Source to Drain diode in relation to power mosfets. I dont know how you plan to use your SIDAC, but you can connect it in just like you would a sparkgap. I would have to see a circuit diagram. By the way, what software are you using to create your schematics? It does a way better job than my messy hand drawn schematics...

[janost]

You can do without the diode if you will not ever have reverse voltage peaks that might exceed the maximum reverse voltage rating for the mosfet.



Yeah, sorry, the minimum holding current shut off works similar to an SCR.
Not sure what you mean about the diode in relation to the SIDACs. I thought we were talking about the reverse Source to Drain diode in relation to power mosfets. I dont know how you plan to use your SIDAC, but you can connect it in just like you would a sparkgap. I would have to see a circuit diagram. By the way, what software are you using to create your schematics? It does a way better job than my messy hand drawn schematics...

Yes, sorry, I'm discussing both at the same time

With the SIDAC I mean that an external diode would take the reverse current, effectivly shutting off the SIDAC?

[janost]

I did a mistake a couple of months ago that killed my first DSO.

I put a FL-tubestarter on the primary side in series with a 230v/24v transformer.

There was like 6VAC on the secondary when the neon was glowing in the starter.

When the bimetal hit and started to pulse, the secondary hit about 200volts and killed the DSO.

So this sparkgap thing works but I want to do it in a semiconductor way