Understanding Guanella Components (Baluns)

RE: Understanding Guanella Components (Baluns)

shabaz — Tue, 13 Feb 2024 17:07:34 GMT

Another follow-up blog:

[mention:1249523469a441d8a81874b821508f44:f7d226abd59f475c9d224a79e3f0ec07]

RE: Understanding Guanella Components (Baluns)

jc2048 — Tue, 13 Sep 2022 09:30:36 GMT

Interesting blog. I didn't know the history side WRT Guanella. I've come across these (theory - no
practical experience) as 'transmission-line transformers'.

It's quite easy to see the characteristic impedance of a line if you have an oscilloscope, a pulse
generator, and a length of transmission line. Here I'm using an Arduino as a pulse generator (four
outputs paralleled), with some series resistance (4x180R) to bring the output impedance of the pin
drivers up to 50R, driving a 1m length of RG58C. This is the waveform at the start of the line with
the far end open, so that the wave reflects off the end and returns to the start rather than being
absorbed by a load.

The plateau is where the wave is propagating along the transmission line. During that period the
characteristic impedance is forming a potential divider with the series resistance and giving a
voltage level of approximately half the drive voltage out of the Arduino. Although not spectacularly
accurate, it does give a way to crudely measure characteristic impedance. Also, by measuring the
there-and-back time, it's possible to estimate the wave velocity of the line (but measure the length
of your line accurately - this cable was sold as being 1m, but is actually longer than that).

Now that I've got a simple measuring set-up, I'll try with some thin enamelled copper wire. I'm also very curious now to see what effect the ferrite has on the transmission-line properties (if any).

RE: Understanding Guanella Components (Baluns)

shabaz — Sun, 11 Sep 2022 15:17:23 GMT

(blog updated with chart for different characteristic impedances)

RE: Understanding Guanella Components (Baluns)

DAB — Sat, 10 Sep 2022 17:47:27 GMT

Nice post.

The intricacies of RF can be very interesting.

We explored the impact of photons having two charged mass objects inside and were amazed at the implications.

RE: Understanding Guanella Components (Baluns)

shabaz — Sat, 10 Sep 2022 15:11:48 GMT

Can't edit due to site problems, but wanted to comment on a mistake immediately because it will cause confusion otherwise. The text

"i.e. 50 ohms to 8 ohms if the characteristic impedances of the pairs of wires is 50 ohm"

should read:

"i.e. 50 ohms to 8 ohms if the characteristic impedances of the pairs of wires is 20 ohm"