Questions tagged [balanced]

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In what situation,we should consider the balanced bridge when we calculate the equivalent capacity?

Question: Find the value of the equivalent capacitance between $a$ and $b$ Solution:Because of the balanced bridge,so the circuit become So \\$C_{ab}=30 \mu //[(4\mu // 6\mu)+((6\mu // 9\mu))]=5\...
779 views

Consistent failure of THAT 1646 line driver IC. What could be the cause?

I work with audio electronics in the touring concert realm and I've been seeing a gross failure of a certain balanced line driver IC, the THAT 1646. Main symptom is no output and most common failure ...
90 views

How to match the length of wire for a symmetrical circuit?

I am new to my current job and one design inherited from my predecessor was as follows. I am wondering if this is the best practice to make a symmetrical circuit. I was told that the two wires (R+ ...
388 views

Convert 3V unbalanced microphone to 48V phantom balanced

I have the following circuit in an existing product, which has a microphone, power switch, LED indicator, and is powered by 2 AA batteries: simulate this circuit – Schematic created using ...
142 views

'true' balanced audio?

I was working on the below circuit, to create a balanced audio output. But have been told this creates a differential audio output, not a 'true' balanced audio output. "A true balanced output would ...
403 views

how to hard-bypass the input of a line driver with a switch?

I want to use a balanced line driver of the type DRV134 or THAT1646. With a bypass switch I want to bypass the IC and send the signal to another circuit instead. In order to null the output of the ...
49 views

Driving Multiple Balanced Audio Runs Off Single Differential Op-Amp Circuit

I am working on an audio project that needs to drive 16 balanced xlr cable runs with stereo differential audio. For this purpose I am using the following op-amp circuit to produce a low impedance ...
230 views

Shielded twisted pair balanced transmission line implementation

I want to send a signal from board 1 to 2 through 20 cm line. I have four channel in differential, First I add them, can I send them through shielded twisted pair like this: Do I need a buffer? why? ...
681 views

How does the CMRR of a fully differential amplifier change with input impedance imbalance?

Most pro-audio microphones provide a balanced output -- this is intended to provide improved noise rejection, and provided the output and line impedances are appropriately balanced, it does. However, ...
147 views

DC Power Limiting Circuit

I would like to know how to build a power limiting circuit. The goal is to be able to combine two PSU's with the same voltage in parallel in order to increase the Power output. From what I've tested,...
5k views

How to properly convert a balanced (line level) audio signal to unbalanced?

I want to connect a balanced line output of a pro grade mixer to a consumer grade power amp that only accepts unbalanced RCA aux in connectors. The mixer has balanced TRS (tip-ring-sleeve) 1/4 inch ...
4k views

BMS without a balance option?

I recently received a Li-ion BMS which has a checkbox called: Balance function: with / without Apparently the BMS does NOT have a balance function. I want to use it with 18650 cells, the ...
318 views

What are the limitations of “fake” balanced audio cables?

I have an AV receiver providing amplified outputs and preamp outputs. The pre-amp outputs are in the form of (unbalanced) RCA jacks. My speakers are amplified and have a balanced input. I was looking ...
145 views

Lithium Battery Pack Discharger

I'm trying to build a circuit that balance each cells from lipo battery by discharging them until all of the higher voltage cells are the same voltage as the cell lowest in voltage. Most of the time ...
2k views

Single supply differential balanced preamp

I'm trying to build a single supply balanced preamp for an electret mic. To further complicate matters, I'd like to impedance balance the mic output to take full advantage of the preamp's noise ...
176 views

Grounding balanced secondary isolation transformer for EMI suppression

simulate this circuit – Schematic created using CircuitLab Which is the best secondary connection to clean the main line power from EMI, line noise and HF harmonics by using an isolation 1:1 ...
83 views

Balance charging connection for 2 cell li-ion

I am designing a circuit powered using two 18650 li ion cells in series, I will wish to charge it with an imax b6 charger with balance output. Is it enough to connect the 3 terminals of the charger to ...
358 views

Transfomation of impedance using a balun

I need to convert 75 ohms balanced impedance to 50 ohms unbalanced impedance using a balun. How do I do that? I am new to this and don't really understand the concept of a:1 voltage and current baluns....
85 views

How to invert one channel of phone output?

I want to connect phone output to a car radio. It has + and - inputs. When I connect left channel to the + input, there is good quality sound, but it's not as loud as CD player. If I invert right ...
1k views

Crosstalk between Wires in a single Twisted Pair

I was reading about the Twisted Pair Cables, and how they implement Balanced Line methodology to cancel out all the noise. All fine and good. However, I just couldn't grasp this one simple doubt: ...
78 views

XLR phantom power microphone mute, redux

Wall of text? Feel free to jump to the four related questions towards the bottom! I had a previous post discussing how to build a pop-free, electronically controlled mute circuit that goes inline in a ...
117 views

Is there such a thing as a fully differential line driver?

I'm looking to find something similar to the TI drv134 (http://www.ti.com/lit/ds/symlink/drv134.pdf), but then with differential inputs instead of single ended. Is there even such a thing? I can't ...
720 views

balanced to unbalanced audio switch

I have an audio source input, that I am putting through the circuit below to create a balanced audio signal. There will be one of these for each channel, left and right. I have been asked to provide ...
106 views

Balanced Charging of ZOP 2s lithium ion battery

Good day everyone, I recently purchased a “ZOP Power 7.4V 2200mAh 2S 35C Lipo Battery T Plug” for a project. I have designed a circuit to charge the battery, but now I am wondering if it is necessary ...
433 views

Soldering XLR Cables together

I'm aware that the structure of a balanced cable is an integral part of maintaining signal quality. If I was to solder two XLR cables together in an effort to make one longer XLR lead, what would be ...
2k views

Why is neutral required in three phase charging of Electric vehicles?

Talking about both three-phase AC as well as DC fast charging (wherein 3 phase AC is converted to DC) in EVs, I think that the 3-phase rectifier represents a balanced 'load'. Therefore I want to know ...
271 views

Balanced star 3ph system

I have balanced star three phase generator 380V with junction point is connected to ground And current through from junction point to ground is I0=0 for that clearly say it is balanced system when i ...
190 views

Op - Amp and Unbalanced Input Differential Signal

Let's consider for instance an Open Loop Op-Amp (for instance with double power supply: VDD and -VDD), which is a good comparator circuit. The sign of its input differential signal (Va - Vb) ...
95 views

Does this audio amplifier do differential filtering?

I was looking at this schematic for a two-channel audio power amplifier. The amp supports a bridged mode by means of an XLR connector and a switch. When the switch is in the XLR position, pin 2 (...
48 views

Adafruit USB LiIon/LiPoly charger - v1.2, charging multiple batteries with series output WITHOUT switch?

On their documentation page, Adafruit offer a tutorial for using it with 2s li-ions. However that also required a 3pdt switch, which would have to be manually thrown. Since in my project I will not ...
35 views

Calulating the total thermal power in three phase system

In my book I have following task that actually has a solution. However I do not understand the solution idea and that's why I'm asking you guys to help me understand that if possible. Why I do not ...
670 views

How does noise affect an unbalanced signal on a balanced cable?

With regard to audio and balanced signals with XLR connectors, how does noise affect an unbalanced signal on the same cable that normally carries a balanced signal? To give some background, I have a ...
469 views

Hum Cancelling Circuit

Consider the following circuit: I was just thinking about how connecting consumer grade unbalanced electronics together has a tendency to generate hum. For example, I have a little mixer that has an ...
656 views

make a buffer balanced

i am still new to electronic and i probably have a stupid question.. i am trying to build a buffer for a piezo microphone following the project on this site: http://www.scotthelmke.com/Mint-box-...
148 views

Undriven element when connecting coax to ground?

In playing around with some RF beacons I noticed that there is generally just one driven element, with the other elements connected to ground if present. I'm having some trouble wrapping my head ...
55 views

Balanced to unbalanced circuit not working correctly?

I've tried to build a balanced to unbalanced signal converter with an TL072. The problem is that if I put a balanced sine signal into it I only get the bottom half of the sine as unbalanced signal out ...
19 views

3 phase 208v leg balance and observed KVA

I have a cluster computer system in a small server room, fed by an 80 kva capable double conversion (480v 3-phase in, 208v single phase out) UPS. This UPS has an LCD display showing voltage, leg ...
40 views

RS485 unmatched line - what will be the impact?

I am doing an experiment where I have a computer with an rs485 transceiver on it and data rate of 1Mbs. an rs485 30m long with Z0 of 120ohm (also have one with Z0 100ohm). at the end of the cable I ...
614 views

When is it safe to ground DC- (specifically audio output)?

With regard to audio devices, if all equipment is unbalanced and there are no DC- connections to earth ground, equipment will generally operate hum/noise free despite large common mode voltages ...
71 views

Troubleshooting Noise/Quirks in Audio Circuit

I am working on a project that takes in a single line-level audio channel and outputs 2 balanced/unbalanced +/- outputs from that channel. I have read a number of the excellent published articles ...