Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [balun]

An electrical device that interfaces balanced and unbalanced lines without disturbing each line's impedance.

An electrical device that interfaces balanced and unbalanced lines without disturbing each line's impedance.

See Wikipedia's article on baluns for more information.

61 questions
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Balun/matching network question

I am having problem to verify what an app note (AN068) explains to calculate Balun values. I would appreciate if someone could tell me what/where am I doing wrong? The summary of the RF part: Blue part is the DC blocking cap, C10-L1 and L3-C11 are…
Angs
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Why is the balun transformer shorted and not simply removed?

I use a normal balun to match my 300 ohm antenna to my 75 ohm tuner (for "over-the-air" digital TV): I opened this balun up and found the typical circuit: Since the second coil from the top is shorted, the top transformer appears to do…
bobuhito
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What causes common mode currents in a coaxial cable?

I have been messing around with a signal generator, an RF current probe and an open ended coax cable. From about 50 MHz onwards, I can measure a significant common mode current if I attach some wires (even short ones, about 2 cm in length) to the…
Cyrus Tirband
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Adding Two Balun Transformers to SA612 Mixer Has No Effect on LO Suppression

I'm experimenting with a SE612 mixer to learn the basis of RF. I read that the mixer can either be single-ended or balanced, and a double-balanced mixer has the best performance in terms of LO-RF isolation, as both LO and RF are suppressed at the…
比尔盖子
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Voltage Balun 1:1

somewhere I have seen that it is possible to build a Balun by using a transformer in the following way: The explanation I have found is that the fact that the ground is only at the primary coil will make that the signal at the primary coil is…
Kinka-Byo
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Balun Polarity Importance

Hello I am picking up a project from someone else who has a built a dipole that is connected to a 1:1 transformer with the intention of using it as a current balun. I have noticed that from documents that the balun is supposed to be built with the…
dwebber
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Is this layout good? (RF - 2.45 GHz)

I finished laying out HACK, my first RF (2.45 GHz) layout. The sensitive part is the connection between the IC (Atmel SAM R21G18A), the balun (Johanson 2450BM15A0015), and the PCB antenna (copied from a TI app note, thank you Texas Instruments!). I…
MickMad
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LVDS to Singled-Ended - Transmission Line Balun Matching

I need to convert a LVDS clock into a single-ended signal. In the past I've used a voltage balun with a center tap on the secondary but I haven't found any good past 1GHz. I need to get to 2GHz in this application and found transmission line baluns…
Spegs21
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Explain how this CCTV video balun actually works?

I am trying to reverse engineer this video balun. It is meant to convert a 100~120 balanced video signal on twisted pair to a 75ohm unbalanced signal. I've removed it from it's housing, but normally there are a pair of screw terminals on the skinny…
Chris
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What does the 25 Ω termination resistor do in a 0/180-degree hybrid power splitter?

The circuit in the picture is a 3dB power splitter using a 0/180-degree hybrid transformer/balun. I see the impedance ratio of the transformer is \$ (14/10) ^2 \approx 2 \$, thus the equivalent output impedance of a 50 Ω input is 100 Ω into a…
比尔盖子
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Does a Center-Tapped RF Balun Perform Better than Untapped Baluns?

To my knowledge, a conventional transformer is a balun - you simply connect a single-ended signal at the primary side, you get the balanced signal at the secondary side - magnetic coupling doesn't care where the ground is. It also automatically…
比尔盖子
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Balun single-ended 50 Ω to LVDS 100 Ω conversion

I have an LVDS differential 100 Ω signal which I want to convert to a single-ended 50 Ω signal. I want to use a BALUN for this conversion. What kind of BALUN should I use here? Some BALUNs have a 1:1 conversion ratio. Some have 2:1 impedance…
user1175197
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Balun for impedance matching?

I would like to match the output impedance of amplifier IC (1.5 + j1.7) with an antenna of impedance (50 or 75 Ohms) at around 950 MHz. I thought of using a balun so that I could avoid the inductor and capacitor.There are 1:1 or 1:4 or 1:10 or 1:16…
Moni
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sx1276 Understanding matching network

I want to use the sx1276 LORA ic as a node that can transmit and receive at 868MHz. In order to use that band of frequency one has to use Higher frequency rf pins of the chip (rfo_hf and rfi_hf). The image i have attached is from the manufactures…
JOHNDOE
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How to properly use a Balun?

I am again involved an RF design and I am unsure on how to connect up the Balun, minicircuits application note suggests that it is dependant on the polarity/phase of the input signals (which makes sense) but I have seen conflicting implementations…
Renegade243
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