Wideband coupling - Transformer Impedance matching (1/3)

[@mikemercury3656]

Excellent presentation: well prepared and thought out and straight to the point; If only there were more channels like this.

[@terrygains8327]

This is a brilliant channel. The host's mastery of LT Spice makes complicated circuit theory so easy to understand. Thank you for all of your efforts.

[@ahbushnell1]

The leakage inductance is very important at the high end. There can be resonances between the capacitance and leakage inductance and resonance between the magnetizing inductance and capacitance. Excellent video.

[@alaricsnellpym]

Loving the detailed coverage of the practical consequences of non-ideal components and how they drive component selection!

[@M0XYM]

This is an excellent channel - it really is. Very clearly explained. I'm hoping Professor FesZ takes us through the building of a radio receiver/transmitter together with the theory and practice - from antenna to audio!

[@pfabri]

Really comprehensive! I was especially thrilled that you touched on the topic of ethernet isolation transformers and digital signals. Thank you for yet another great and informative video!

[@susceptibility_]

Telepathy works, because I was looking for transformer knowledge, and you have just made a video about it :D

[@pbaemedan]

FesZ, great video. Thank you for all the hard work. LTspice is a great tool for the normal electrical engineer. Your willingness to provide examples lets one to do the what if sincero.

[@paulcohen1555]

AGAIN: EXCELLENT AS USUAL.

[@hedleyfurio]

You have excellent signal to noise ratio - hopefully lt spice will sponsor your channel as you clearly show it’s value over a range of applications 👍

[@FesZElectronics]

Thank you for the kind words! I guess you can perform all of these simulations in any proper circuit simulator, the nice thing about LTspice though is that its a free program.

[@therfnoob7697]

just found this channel! Great work! thanks

[@nomadr1349]

This channel is almost as good as w2aew!

[@rjordans]

Another nice one! Maybe one you have covered filter design you can have a look at bandpass filters with impedance conversion. Also a nice way of getting higher bandwidth matching. There are some nice tables around that give you the component values for different ratios of input and output impedance.

[@Mike-H_UK]

Very interesting - many thanks. One addition complication that I found: you mention using 'magnetic cores' in order to maximise the 'L' for a better low frequency cutoff, yet reducing the 'C' for a better high frequency cutoff. This is 100% true, but practical cores have the disadvantages of increasing the 'core loss resistor' and this increases thermal noise - sometimes unacceptably, and also the real part of the complex permeability drops off for higher frequencies and this can in turn limit the high frequency response. Thanks again for a very educational video - you obviously spend a lot of time on these.

[@FesZElectronics]

You are indeed correct - any magnetic core will start to loose permeability as frequency increases - first the real part of the permeability drops, and the imaginary (lossy part) increases, then both fall down. As with everything, I guess its a matter of handling the various compromises to get the best for a specific situation. You will never get an infinite BW, so you could just use a core that keeps its real permeability as long as its necessary. I won't be perfect, but it should be better than just using an air core.

[@mikeh2909]

@@FesZElectronics I find this an amazing area where circumstances always arrange themselves to stop the engineer doing what he wants! A ferrite-core with a high frequency before the real part drops off (and the imaginary part rises) typically had a relative permeability of ten or so (eg Fair Rite mix 67). So designing a transformer with good low frequency, high frequency and low noise is next to impossibel. It reminds me of an old adage in cycle racing: low cost, lightweight and strong frame - pick any two!!!! Thanks again.

[@curtstacy779]

Thank you very much! great explanation.

[@R73CH]

Very nicely explained! It is worth noting that it works for low frequency applications. Cannot be applied for RF signals.

[@hubercats]

Excellent presentation!

[@__--JY-Moe--__]

👍

[@hyoksong1816]

Excellent tutorial.

[@adam207321]

Impedance matching is a wizards art...ask any HAM :D So I guess after this one were building a transmitter? I wish lol. The interlaced winding is called Bifilar wind as far I know. I used this in my SMPS transformer wind. One problem that does arise with bifilar winding is that the interwinding cappscitance shoots trough the roof while the cappacitance of the windings each can be minimused to almost a neglegctable degree for frequencies achievable at home..and thats a lot of MHz

[@FesZElectronics]

I guess that for an SMPS this type of bifilar winding is not ideal, but for the impedance matching transformer I guess its acceptable, since it will only reduce the BW a bit - but as long a you need a narrow BW anyway its ok. In parallel I am working on a series on the various classes of amplifiers, so I will try to apply these insights there.

[@adam207321]

@@FesZElectronics it is not ideal due to the interwinding cappacitance and the compromise of glvanic isolation..however if you want to achieve strong magnetic fields in a small perhaos single layer coils..lets say you have a ETD49 bobbin amd the primary turns out to be just 3 turns...yeah 3 turns. Now to fill the entire lenght of bobbin youd need rather thick wires.. instead we take thinner wires and wind them the same way as a bifilar winding but we connect them all in paralel. This way you save a lot of space and improve very high frequency response as after a given frequency range skin effect truly hinders the performance of thicker wires. Its also a much more space efficient way of make such a high power low turns coil. I hope you understand what I mean by this

[@rogeronslow1498]

The type of winding is called interleaved, not interlaced. And with careful winding design you can significantly reduce the intra-winding capacitance.

[@bbigboy01]

Great presentation. Can you suggest how I could model a 50 ohm input impedance circuit driving two separate secondary 50 ohm windings, each connected to a 50 ohm antenna, one circuit of which has phasing control. I want to be able to electrically steer this 2 element antenna array.

[@Bianchi77]

Nice info, thanks :)

[@dmyegorov74]

Great info, thank you!

[@pfabri]

For a second I thought I was going mad when I saw your pen move from one side to the other UNDERNEATH your writing.

[@FesZElectronics]

For time constraint reasons I found it easier to just fix a writing mistake that way...

[@australischemediengemeinschaft]

Für diesen Fachfilmbeitrag vergeben wir von maximal erreichbaren 10 Bewertungspunkten: 10

[@waterfuel]

Help needed! How do I match impedance of inverter16v AC output SOURCE to 16vAC isolation transformer primary, that I have to hand WIND, for 4 ohms load of 32v AC 6 amps secondary ? Do I use the ohms of primary 16v + 12 amps division or the resistance .06 ohms of inverter output contacts terminals at 20khz frequency? Voltage and turns ratio same as 1:2. The online formula for inductance value of turns requires reactance value in ohms , at the frequency of source.

[@petzhang3019]

Great video. Question: 18:12 why the secondary side sees the turn ratio of 2?

[@FesZElectronics]

Well, the primary is L3; and the secondary is L3+L4; the total secondary inductance is the 2 individual inductors + the mutual inductance - that adds up to 4xL3; the turns ratio is therefore 1: sqrt (4) = 1:2; another way to look at this is that L4 has the same number of turns as L3; so L3+L4 has twice the turns as L3

[@grzesiek1x]

But one thing is really confusing to me. Let's say I am building a simple receiver for 27 MHz. I have a schematic from a book and the author say I need a piece of wire 35 cm and a capacitor 5 pF for my antena circuit and after there is there is a beginning of regenerative receiver circuit with a transistor etc. but what I don't understand is how that antenna is matched to the amplifier??Eveywhere people say 50 ohm source matching witth the amplifier but from another side I hear that the high impadance is very important at the beginning of the circuit in receiver. It sound really coontradictory to me :( Plus the signal is very weak so if i unerstand it correctly anything with low impedance like 50 ohm would completelly wipe out the signal and I would need a very high impidance but why everybody says 50 ohm . I don't get it. Maybe my understanding is not correctly or I don't know ... Anyway I know this is very important because otherwise I will stay with low range receiver forever :(((( My design works perfectly fine for max 3 m but commercial receivers work even for 100 m how do they achive that . I have experimented a lot, I look in engeering books etc. (usuelly they are not very usufull because old books talks always about valves or tubes etc. but from the other hand modern books talk about integreted circuits etc. and i have noody to ask but I know that I am very close to the solution 🤔I have some lack of knowledge (I am not an engineer and I started my electronics projects 3 years ago) but I try to learn as much as I can in my free time.

[@grzesiek1x]

5:30 or maybe i would need a transformer which has turns ratio of 44 to 1 so i will have 100 000 ohm at the input (for example from the antenna) and 50 ohm at the output for the HF amplifier for example?

[@BIGRIP87]

I love transformers

[@troy6882]

What's in that Peck???is a interesting one no especially with mixed units and I'am a beginner sort off!.😃😄😁😆😅 5 Smiles. Or not signal but load regulations via a double line one resistor one a amp inductor to stabilize volt regulator set put to a 5v 4 to 15odd volt and watch as the 5volt even at 32volt don't work the one above is so they don't over heat or a component heat load balancer to your caps regulations so it only gets warm😁.

[@grassrancher]

Hey, I know this is an elementary question, with likely a very obvious answer, but I'm struggling with the math @6:36 with how the inductance ratio of 2:1:1 results in an impedance ratio of 1:1:1 (written in the LTSpice comments) in your example of two secondary windings.

[@FesZElectronics]

I'm not sure I have a very good answer for this.. The 2x 50R loads are seen in parallel by the source, so its an equivalent 25R load - a 2:1 impedance/inductance ratio is needed. So to get both loads exposed to this ratio the transformer is 2:1:1.

[@JAYDELROSARIQ]

Kohms ml mu even pulses by Hertz AMPS WATTS -+BATTERY..LIV AC LINE NO NUTRAL GROUND NEGATIVE I LIV PUSHED JLQUY >|

[@R2AUK]

👍