By the way, already watched the previous three vids with great interest because I'm trying to learn how to design and build my own MLA. I just obtained my ham radio license upgrade to Amateur Extra here in America and want to learn how to design and build a MLA while all the studying for the license upgrade test is still fresh in my mind so I can can understand and comprehend the process.
Great video. A lot of high-current inductors are wound with wires with a rectangular cross section with one dimension large and the other dimension small (maybe two skin depths). This type of wire (or maybe even just copper tape) could be used in a coil with an inter-coil spacing of four diameters. Any idea how this would perform relative to round or litz wires?
The rectangular wire (or copper-tape) is used to get a fill-factor near 100% so that the volume is filled as much as possible with copper. en.wikipedia.org/wiki/Coil_winding_technology This is advantegous in motors/generators, chokes, solenoids, voice coils etc, But it has nothing to do with skin-effect or proximity effect (at least that is not the primary reason to use rectangular wire). I don´t see any advantage over round wire. The proximity effect would be even worse because more area of one conductor is near to it´s neighbour.
i cannot find the Excel sheet. and the other thing i wanna ask that is as you showed a high source impedance than in case of wireless power transfer how the maximum power transfer theorem can b applied because in that case it seems that the load resistance must be very big in case to transfer maximum power.
Yes. A tank-circuit is a high-impedance source. A typical value for a high Q-factor LC tank-circuit is from 100kOhm to 1Megohm. That is why most crystal-radio circuits don´t work because people don´t match the (dynamic) imoedance of the rectifier diode and the load-impedance of the earphone to the output-impedance (=resonance-resistance) of the LC tank-circuit. Nevertheless you get progressively more power out of an LC tank-circuit if you increase Q-factor. The resonant voltage and the resonance-resistance grow linearly with the Q-factor. But because maximum output-power is Voltage-squared(!) divided by output-impedance, the maximum output still grows linearly with an increasing Q-factor. (Of course only in case of matching load-impedance). I will discuss this extensively in a forthcoming video-series about the "perfect" crystal-radio set. Will come in 1-2 months. Open "show more" in the description. There you find the download-link: www.kainkalabs.com/upload/index.php?f=15894916880b3e
thankyou so much for your quick answer. According to your detail explanation i can assume that the output power will depend on the value of the voltage, so if i can increase the output voltage of the tank circuit by increasing the Q factor only then the i can get more output power. so output power is equal to v^2/source impedence+load resistance.
Well not quite. Take e.g. a frame-antenna as a general example for loop-antennas. (BTW: Loop antennas can be operated in two different modes: resonant mode as in an LC tank-circuit or untuned short-circuit mode. I only discuss the resonant mode here) The output voltage depends first of all (as in all antennas) on the incident voltage at the location where it is set up. The output voltage of a frame-antenna (without any load) then is dependent on the cross-sectional area of the frame antenna and then the Q-factor. Both can be summed up in a formula: de.wikipedia.org/wiki/Rahmenantenne#Grundgleichungen (this mathematical deduction is only available in the German version of the Wikipedia-entry) All in all the output voltage of the frame-antenna grows with the third power (!) of the diameter of the frame (already taking the Q-factor into account) But this output voltage will be severely reduced if the load-impedance is not close to the output-impedance (=resonance-resistance) of the frame-antenna.
one side question I read your excel sheet, I wanna know that after doing a certain calculation we found the values of Q factor and skin depth but the Q factor depends upon the frequency. So what is the limit of increasing the frequency in order to achieve a high Q-bearing in mind losses due to skin depth and proximity effect. I want to ask how much can I increase the frequency for particular dimensions of the antenna. Thanks
Wow they censored the hell out of your website I kept getting a thing that said hackers may be trying to steal your identity and show your website link as I could dangerously and I had to hit advanced just to get the option to proceed to this site. This also happens every time I try to switch to different parts of the site. Gotta love the feds
