Tabletop Tesla Coil

In this video I'll show how i built a battery powered solid state tesla coil that fits on a desk or a coffee table. The coil uses a "slayer
exciter" circuit with an RC snubber and reverse protection diode to avoid damaging spikes of voltage/current during "hard switching". In
addition, 3 FETs are used in parallel to spread out the heat load, which makes the circuit far more reliable.

In addition to those changes, I've buffered the MOSFET gate drive with a push-pull pair consisting of an NPN and PNP transistor. This allows the

gate to be turned on and off much faster, and allows more control over the gate voltage by using a resistor divider on the base of the

transistor(s).

The circuit is interrupted with a 555 timer. It runs at approximately 60 hz and 30% duty cycle. This gives the arcs a more sharp/jagged shape,

but also reduces the power consumption and heat load.

Another useful feature in this driver is the low voltage cutoff circuit, which shuts off the gate drive transistors if the supply voltage falls

below 22V. This ensures that the lithium battery won't be over-discharged.

The maximum arc length i've observed on this coil is approximately 4" (10 cm),
which is very impressive considering that the supply voltage is only 24V.

You may have also noticed that I used a sharp electrode for a breakout but no toroidal / spherical top load. This is to reduce
A few specs:

Primary Turns: 2
Secondary Turns: ~1200
Secondary Diameter: 3.5"
Secondary Height: 6.0"
Input Voltage: 24V (Nominal)
Current Consumption: ~4A
Operating Frequency: ~300 kHz
Interrupter Frequency: ~60 Hz
Duty Cycle: 30%
Snubber R/C: 2 Ohm / 54 nF

Parts I used:

IRF640 (3 in parallel for driving the primary)
2N3904 / 2N3906 (gate drive transistors)
2N3904 for undervoltage cutoff / interrupter pull down
MUR120G (Rail diodes)
NE555 (Interrupter)
LM833 (Undervoltage cutoff comparator)

Music Used:

Kevin MacLeod - George Street Shuffle
Kevin MacLeod - Lobby Time
Serge Pavkin - Crystals

[Hwastooshort]

I really like the type of videos you make. idk they just feel right. no bullshit no calls to action no hyped up voice, just you and your project like old youtube

[MrElapid]

Excellent vid. Nicely crafted! Just starting out here, built a VTTC with 2 572B triodes. Works well, I think I'm hooked. But your small portable unit is remarkable. Also you present yourself clearly and intelligently, Thank you! Old and retired here, can't deal with too much theatrics and weirdness.

[Spirit]

One of the best explanations for the design and iteration process! And a pretty clean build too.

[littleshopofelectrons]

Nice coil! I made the same "insulated switch" discovery when I built my 833C VTTC. Whenever I would touch one of the toggle switches I would get shocked! I also thought initially that I had a bad grounding system but it was current being induced into my body by the electromagnetic field.

[MervynPartin]

Very inspiring- If I still had all my workshop machinery, I would have a go at this. The demonstration was as good as it gets and well done for the additional safety warnings about the dangers of the high frequency affecting the surrounding metalwork.

[curiousviewer]

Nice as always! Loved the development of the circuit and the Slayer Circuit animation.

[JATmatic]

I think this video revived my dream of small tesla coil build!! I didnt think such simple driver could work with just 12 volt input.
I have exactly same problem as on video start - bad coil feedback -> lame arcs.

[AppliedMathematician]

This perfectly shows why I stopped my last circuit design. I did design simple circuits many years ago, really trivial stuff, but even there you start with an simple idea, and then fix the issues ... and simple becomes complex fast. Since I lack experience I can not judge if my finished solution is actually ok or an abomination that still works somehow. So just decided to delegate that when I actually need a circuit. For what I do, i.e. abstract systems design, I just need to know that technical solutions exist.

[xntumrfoivrnwf]

Videos like this make me nervous, but not for the reason one may think. I've killed more than a handful of devices (bench PSUs, function generators, etc.) from running/testing my tesla coils next to them. So seeing you run it next to your nice scope is frightening. I don't know if my problem is cheap electronics that I had or what... :(

Great build and video as always!

[RAVI]

Great video. Highly appreciate it & love what you did. Where simplicity is, you are there. Keep it up.

[simonward]

So built up this circuit and it works flawlessly good Job! getting about 2.5 inch off the breakout at 24v nothing getting warm other than the snubber resistor which is doing its job!, time to make he voltage cutoff im debating to use a lm358 instead as this is all ive got in my parts bin, cant wait to get it in a box and portable, thanks for showing how its done ;-)

[jstro-hobbytech]

Reign in Blood!!! Man i had trouble learning that riff as a kid. Sweet video.

[ianfisher]

Fantastic project for the HV enthusiasts! Thanks for sharing.

[JoinTheTechnicians]

(Edit: you earned a subscriber!)
I love this video. It is so honest and informative, i'll use this video as a guide to make a top-notch tutorials in my own future videos. Thank you for sharing your amazing information style and presentation skills.

[omsingharjit]

Same here, you can also use relay for particular low voltage cutoff levels .

[MainelyElectrons]

Love your videos. I remember having a plasma globe when I was 10 and quickly learned a penny could be balanced on top and cause very similar shocks/burns depicted in your video! Not to the same intensity but nearly identical burns

[kbe.]

5:30 you got drains and gates interconnected on your diagram :)

[OMNI_INFINITY]

That jar was the star of that show. Surprising that only an empty vacuum tube can do that

[MasterIvo]

I like that slayer mosfet exciter with BJT's

[goranjosic]

Thanks for the tutorial and great explanation in the details!
This will be my next hobby project! :)