Sciencemadness Discussion Board

Illuminating Gasampules

Kloberth - 14-3-2024 at 09:18

I have built a periodic table for presenting my projects and i want to be able to illuminate gasampules. What kint of circuit would be the best for that. perfect would be one where the coils can be made into a flat face on the back of my periodic table.

I thought of some kind of solid state tesla coil but am unsure if it would work when small enough no to distract from the actual periodic table.

Any ideas?

[Edited on 14-3-2024 by Kloberth]

Sir_Gawain - 14-3-2024 at 09:39

The first thing that comes to my mind is a slayer exciter powered pancake coil. It's a very simple circuit with only a few components.
You could also stick two pieces of aluminium tape to each ampoule and wire them to a small neon sign transformer. That would probably be more reliable.


[Edited on 3-14-2024 by Sir_Gawain]

Kloberth - 14-3-2024 at 09:52

Where would i place the primary?
On the outer ring of the secondary or also as a pancake under the secondary?

Sir_Gawain - 14-3-2024 at 09:58

I think it's usually placed under the secondary, but you could try both and see which works better.

Kloberth - 14-3-2024 at 12:08

Thanks!
Parts are ordered ill try to throw a circuit together and see what works

Sir_Gawain - 14-3-2024 at 12:28

What transistor are you using?

Kloberth - 14-3-2024 at 23:46

I have ordered a npn and pnp transistor kit and will try a slayer exciter with less current and an 2N2222 i guess and i also have a higher powered transistor in mind and found one laying around (Datasheet atteched), I would guess this one wouöd work in a circuit like the one from https://youtu.be/wWIeUsnqkRk?si=8dXwbloiED2jXQ8x

Screenshot_20240315_084139_Opera.jpg - 372kB

Sulaiman - 15-3-2024 at 03:50

I have played with a couple of these
https://www.ebay.co.uk/itm/353994827404
Very nice, and cheap.

Easy to change airgap and/or replace primary winding.
As-is it should suit your needs.

PS I've not tried but I think that one of these
https://www.ebay.co.uk/itm/375304429891
may be even better.

but if you're in the mood to wind-your-own then ok

That mosfet is beefy - slight overkill ;)
(just check that the large gate capacitance will not be a problem in your design)

[Edited on 15-3-2024 by Sulaiman]

Kloberth - 15-3-2024 at 04:13

Damn these are cheap Thx for the tip.

The thing is recently the interest of electronics sparked in me and i want to build a powerful tesla coil myself talking something like a plasma flame. I want to understand the working and to begin ill try building a sstc myself.

Sulaiman - 15-3-2024 at 04:59

An sstc is ok if you copy a working design,

Frankly, if you do not have access to an oscilloscope then don't try experimenting with an sstc as one of your first projects
- very high risk of failure.
I strongly suggest that you start with a kit
OR
have have a plethora of spare components available ;)

[Edited on 15-3-2024 by Sulaiman]

Sir_Gawain - 15-3-2024 at 08:44

This might not be the best for a first project, but after I finish building my 3kW spark gap coil I want to build one of these. My first SSTC was this very simple one. It works great for only having four components.
I've had both of those kits that Sulaiman mentions; the tesla coil one works pretty good, but it does burn out easily.

fx-991ex - 15-3-2024 at 09:29

Quote: Originally posted by Sulaiman  
I have played with a couple of these
https://www.ebay.co.uk/itm/353994827404
Very nice, and cheap.

Easy to change airgap and/or replace primary winding.
As-is it should suit your needs.

PS I've not tried but I think that one of these
https://www.ebay.co.uk/itm/375304429891
may be even better.

but if you're in the mood to wind-your-own then ok

That mosfet is beefy - slight overkill ;)
(just check that the large gate capacitance will not be a problem in your design)

[Edited on 15-3-2024 by Sulaiman]


Those are great kit, wish i had access to this a few decades ago.

When i need high voltage i usually get a 555 timer(or a tl494 from a old AT power supply, but the circuit is more complex) and a high power mosfet, wind the coil myself like an auto-transformer or i get a flyback from a crt and just wind a primary coil over the ferrite core myself. I adjust the duty cycle or frequency for setting the output power.




[Edited on 15-3-2024 by fx-991ex]

Sulaiman - 15-3-2024 at 14:15

In that case, best wishes and good luck.
A large sstc may arc over gas sample phials,
The first module is a blocking oscillator
(the core saturates each cycle, not suitable for large cores)
and the second is a 'slayer'.
either is easy to DIY but the modules are cheap.

Kloberth - 26-3-2024 at 09:09

i am currently building a spark gap teslacoil with a 10kv neon sign transformer as the powersource and am building the cap with multiple 630 v capacitors. to unload them after firing the coil can there be used 3mohm resistors in paralell with every capacitor or do i need a higher number cap?

Sulaiman - 26-3-2024 at 10:12

There are forums for this but..
I recommend a bleeder resistor for each capacitor
(or at least for each set of paralleled capacitors),
Theoretically not required - simple theory.
Messing with a hv cap bank is less stressful when bleeders are present.
You could calculate power loss, voltage decay rate etc.
but by default I used 33M 0.5W because I bought a lot of them.

10kVrms x sqrt(2) = 14kV = a minimum of 23x 630V caps in series,
(I'd use more for safety, or less for economy - or not, if I'm unlucky).
Consider series inductance of the overall capacitor bank...
Make current loops as small as possible.
(areas enclosed by current carriers, including connecting wires)
BUT also maintain insulation distances.
Surface tracking is a big problem.

If your spark gap produces thin bright loud arcs you're doing well.
Fuzzy plasma-looking arcs indicate a poor spark gap,
or sometimes a high esr cap bank.

PS I hope that your 10kV NST is of the heavy iron core transformer type,
Not the modern electronic inverter type - which I'd expect to be problematic.

[Edited on 26-3-2024 by Sulaiman]