@DataRocks
Here is a the circuit which should be pretty much what you have on the little board you're using:
from:
http://kaizerpowerelectronics.dk/general-electronics/royer-induction-heate
I don't want to just go off about capacitors half full of electrons, so to keep this post somewhat relevant to non technical folks, I'll confuse you all with a partial mixed analogy of what's going on here..
The circuit is *kind* of like a swing. If you take a fire-hose and spray the swing from the front or back, it will push it a little. If you spray it from the front, then from the back, then the front, at the right time, that swing will accumulate some energy in it's swinging. A real swing transfers energy between kinetic (swing moving fast) and potential (swing is high up, and has potential to be dropped down and accumulate kinetic energy). The swing is like the work capacitor and coil, exchanging energy between an electric field in the capacitor, and a magnetic field in the coil.
That mechanism which makes sure the front and back hoses don't both turn on at the same time is D3 and D4, which is crucial to the circuits functionality. Basically, by one being on, it turns the other one off. The transistors are like the tap on a hose. Easy to turn on and off, but with enough water pressure could pack quiet a punch. D1 and D2 are there to limit how hard you can turn the taps on and off. They're only necessary if you have enough energy to brake the taps. R1 and R2 are to prevent the taps from slowly slipping into the wrong state.
Now R3 and R4 - those are the little elves trying to turn the taps on. Somebody has to turn them on, so we need those. They don't need to be terribly strong cause all the energy is in the water pressure. This is where you can use a smaller tactile switch. If you cut the voltage off from R3 and R4, the circuit will be OFF.
In the circuit above, you would have to detach the left side of R3 and R4 from the supply voltage, and connect them through a switch.
On the ZVS modules used, like on the image below, my bet would be to lift one side of resistors R1 and R3, and connect them to the voltage source via a small tact switch. Which side is left up to the modder to figure out. If there's ANY uncertainty after my confusing babbling, this mod should be avoided.
As for rating,
@hooglas it... depends.
Let's take a wire for example. A specific gauge wire has a 'rating' - usually determined by the maximum amount of CONTINUOUS current that can flow through it before it gets more than X degrees hotter (and starts to melt the insulation, or itself and more..). However, you could almost definitely get away with a lot more than the rated current (or a much smaller wire), *****IF**** it's for a very short time, and the wire won't overheat. The circuit designer needs to take all sorts of things into consideration though, like what if someone leaves it on, or if something can't shut itself off, so use case is KEY. Ideally, a circuit should survive a fault condition indefinitely.. either by turning something off itself, or dissipating enough heat to prevent itself from overheating at least till the batteries run out. You also need to take the end user into account. For instance, if the circuit designer or builder is operating his or her own device, and can supervise themselves (yes, a difficult task to do in vape design when you're continuously testing
), they will more likely use it correctly. In the absence of supervision though, someone else may not do things right. So I allow myself to build things way out of spec sometimes and use it cautiously, but I'm not likely to give them to my friends to play with by themselves until they've been built to a certain spec, and I know it behaves. Often you can design in a weak spot - something that will give way before things go poof. This can be a proper fuse (which are also tricky to 'rate'), or a thin trace on the board that will just burn out (a printed fuse). Adding a warning system is also beneficial, like a very visible LED that's on while the device is on, so it won't sit there burning up unnoticed unil kapoof.. don't go kapoof, just click click puff mmkay
This is similar to a batteries continuous discharge rate, which is much lower than the pulse discharge maximum. all depends what you're doing with it..
hmmm.. ok enough babbling for now