Basically the circuit will be driving a capacitor in parallel with an unknown load which could be capacitive, inductive or resistive or a mixture. I was simply not clear enough.
Docedison:
Resonance is defined as the frequency where XL and XC are equal, at that point they cancel out and the resultant is just the resistance of the circuit. The formula are somewhat difficult for one not familiar with the concept. In your description of combined reactances, inductive and capacitive the values for XL and XC are opposite in sign relative to each other and add algebraically. If for example if the XC was -180 ohms and XL was 90 ohms them the resultant would be -90 ohms. -reactances are capacitive and +reactances are inductive, so if XC =1/(2 X 6.28 X F X C) then 1/C = XC/6.28/F or if positive (inductive) L = XL/6.28/F (C=Farads and L = Henry's). Frequently small value reactances are used to negate other reactance's... one example is power factor correction where typically the load might be inductive in nature (lots of big motors) and provide a mismatched load. Remember that max power transfer occurs where Xload = Xsource (for ac circuits) a capacitor equal to XL (load) is placed in parallel with the load to cancel out the inductive part of the load.
Got that almost 100% The problem is that the circuit is kinda-sorta a type of "power supply" and you do not know if the output will be a 100 Henry inductor or 1 Megaohm resistor or a capacitor. If the inductor is big enough, it may completely negate the effect of the capacitor.
The technique used in driving capacitive mosfet gates is to just 'swamp' them out i.e. provide a drive impedance so low as to force them into a minor consideration.
Wouldn't the 2N2222 driven to saturation provide sufficiently low impedance to have a decent rise time? I only need to run it at around 10KHz maximum.
Another perhaps better analogy would be parallel resistances. Assume a 10K resistor in circuit and the value might need to be 2K2 ohms and since (1/Rt) = (1/R1) + (1/R2) {Formula for the parallel equivalent resistance of 2 resistors).
We can say that (1/Rpar) = (1/Rreq) - (1/Rcir)... `(1/2200) = .0004545... and 1/10000 = .0001... therefore .0004545... - .0001 - .0003545... = .0003545...Rreq = 1/.0003454... = 2K82 ohms and the proof is 1/Rt = 1/10000 + 1/2820 = 2K2 ohms.
Now I am confused. What does "2K2" and "2K82" resistors mean?
The only difference between DC and AC is the sign of the reactance.
So basically inductors and capacitors are opposite from each other and what a capacitor does on AC, an inductor will do on DC and vice-versa.
Long and complicated until you have done it a few times but trivial with a little experience.
Not all that complicated but slightly confusing.
In Closing capacitive reactances I.E. Mosfet Gates are usually driven with a generator that is at least 1/10 the impedance of the gate being driven.
This should not be a problem.
The math and descriptions would occupy several pages and would need to come from 3 different books, Much too long
Too long indeed LOL
, I think that if you were able to follow my reasoning so far you have some third year electronics theory education.
I do not.
I also think that If you are reading this sentence you are either glassy eyed or seriously interested in the topic of impedance matching.
Actually the latter is more true.
This subject is very complicated as the available gate drive current is a function of the Rise Time of The Driving Pulse not it's Amplitude since we are driving a capacitor. Remember that Rise time is piece-wise equivalent to frequency and that XC (Gate impedance) is an inverse function of frequency.
In my experience, microcontroller pins usually have decently sharp rise time since I have put them on a scope before.
Now lets hope you have experience with OpAmps and current sensing since its another topic I am pretty new to and will probably start another thread soon.