Not true.Unfortunately 2.2mH for the L implies 46pF for the C, the wdg C will almost certainly be larger than this for 330 turns as suggested in post #22
thus 500kHz will not be able to be reached - the capacitance attached to either end of the L must be considered also - if it forms any sort of closed loop ckt.
I didn't test 5000Vac 500kHz before, but similar configuration.@ Taihung - do you have experience with 5000 Vac @ 500kHz ... ?
Not true.
The inductance can be tapped at any point, likewise the capacitance can be tapped, which is the more usual way of matching the tube impedance (about 4.5K here) to the load impedance and produce some low pass harmonic filtering for free. Clearly you are not a radio frequency guy.
Pi couplers are ubiquitous for impedance matching in the radio world.
A long single layer air cored coil will have negligible capacitance end to end. Similar tube circuits can be tuned to at least 100+ Mhz very easily in radio transmitters without any difficulty at all.
A single layer wound on a toroid will certainly have some capacitance down to the core, but the effect of that depends on the resistivity of the core material at the operating frequency. Very low loss material such as the -2 powdered iron material should not have much more effect than air on capacitance.
Resistivity is pretty much tied to eddy current loss, and extremely high resistivity negates capacitance.
For several reasons powdered iron is more preferable than ferrite at radio frequencies.
But I agree that the much higher permeability low frequency ferrites for example, do have this problem of capacitance down to the core.
Distributed capacitance is a much bigger problem with multiturn layers, and layering turns only really becomes necessary in a transformer where the whole thing must fit within a magnetic core of some type..
Taihung, yes quite right.
Often the load reactance/impedance can be rather uncertain as for example induction heating, and driving ultrasonic transducers. Phase detection, or making the reactive load part of an oscillator circuit ensures resonant operation, even if the operating frequency moves around. Many other ways to do this too with phased locked loops for example.
I don't have model for sim to design the L.I love it - by the way 5kV rms is 7070 Vpk on the sine wave, the sim explains all, so easy - is there a way for the sim to design the L ? Mr warpedspeed keeps changing his mind about the best way ...?
That should not be too difficult.The problem is how to buy/ create 1nF capacitor with 20A peak-peak and withstand > 5kV. It takes time or expensive
I don't have time to read back formular and simulation this complex model@Taihung, how much capacitance do you think there will be in the inductor ?
It nice.That should not be too difficult.
They are called "door knob capacitors" take a look on e-bay.
There is one there now, 1nF only 4Kv though, only six Euros.
https://www.ebay.com.au/itm/293081494805?hash=item443d04b515:g:L~YAAOSwVx5gNR-W
Something vastly larger 1nF 12Kv for twenty seven Euros.
https://www.ebay.com.au/itm/293567537256?hash=item4459fd2068:g:e7YAAOSwQqZcJKZG
Just be patient, the perfect capacitor will eventually show up.
Dont'agree. NPO ceramic capacitors are as well as film capacitors for these applications. Down to 1% tolerance and effectively no voltage dependence. There are even better for RF due to higer SRF.For filter & resonator, example in audio application wouldn't like use ceramic capacitor. Often use correction capacitor as film capacitor.
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