Questions tagged [isolation]
Allowing for the flow of power or information without shared electrical nodes
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Puzzle how isolated RS-485 (ADM2582) sends signal without signal ground
Galvanically isolated RS-485 surely needs a signal ground, which leaves me puzzled about the following circuit -- which apparently sends the RS-485 signal correctly without the isolated grounds being ...
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1
answer
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Isolation voltage spec in transformer
Could you please help me understanding this transformer spec?
I am planning to use HCTSM80101AAL transformer and I would like to make sure that I am referencing the proper specification for voltage ...
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0
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2
answers
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How is my isolation transformer not short circuited?
I received a 3 phase 240 to 208 isolation transformer, and I am unsure how the current configuration (as it was shipped to me) would not cause a short circuit. When I do an ohms reading on the high ...
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answer
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Floating output voltage in USB chargers?
A USB charger is usually galvanically isolated from mains for safety reasons.
If I touch the output connector while standing on the ground (i am at earth potential), will I get a shock? I think yes, ...
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Isolate battery from a charging circuit... to use a stronger charger
I have an inverter that currently uses a single 7 Ah lead acid battery.
While the rating of the inverter is sufficient to my purpose, the battery does not provide nearly enough run time, and being ...
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0
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IEC61010 applicability for non-measurement category rated circuit?
I have measurement circuit that will be rated for CAT II 300V but do allow input voltage of over 300V up to 1kV. In IEC61010 6.7.3, "Insulation for secondary circuit derived from main circuits of ...
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3
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How to isolate audio signals from each other using op-amps with the same single supply?
Reuploaded corrected picture, as the old one was with confusing ground connections:
I am new here, so please be patient if I'm doing something wrong. I really need some help as I can't figure it out ...
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0
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Why are USB galvanic/isolators needed on battery operated devices?
Why are galvanic/optical USB isolators used?
I am an astro-photographer who does imaging at remote site locations on battery. I never encountered galvanic/optical USB isolation in devices until ...
0
votes
1
answer
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Half-bridge driver ground loop elimination
I built this half-bridge driver using a generic Schmitt trigger/hex inverter IC and a 555 timer as the square wave generator. By varying the value of the resistors, the dead time can be adjusted and ...
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votes
1
answer
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PoE: PSE isolation requirements
On the robot I'm currently designing, there will be several connectors with PoE ethernet and supply voltage (0 V, 24 V) and some other signals (referenced to 0 V).
I'm unsure if I need isolation for ...
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0
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Read voltage (isolated circuit) from 24S Li-ion battery pack and output 0-5 V signal
I am finishing up a EV-conversion and everything works well except the SoC display.
The BMS I am using outputs 0-5 V to indicate the SoC but the output pin for this signal is broken from the previous ...
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vote
1
answer
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RS232 : dedicated signal ground or common with power ground?
I'm designing the PCB for a robot, where I plan to add some connectors for external RS232 tools (provided by the client).
Each connector will provide power (either 24 or 48V, at 5A max) and an RS232 ...
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0
votes
3
answers
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Eliminating Noise from Audio Amp Board Input
I made this project by shajeeb (linked below), and I am having trouble with noisy ground lines. The circuit I made is the same as the diagram below except for where I connect the speaker and amplifier ...
0
votes
2
answers
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Isolating USB3 with an ADUM4160
I've not played with USB much besides the ordinary FTDI UART bridges. Recently, I have reason to use an FT601 with a USB3 port configured for super-speed operation. As this is connected to a fairly ...
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Driving Gate from MCU (using 6N136 and TC4431)
This is my first time trying to use this optocoupler (6N136)
I'm trying to control a MOSFET gate with the least switching delays (rise and fall timings) possible, while making the MCU isolated from ...
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Reducing Isolation Transformer Leakage
I watched this video and wonder if its complete separation of primary and secondary coils is the normal way to wind a low-power isolation transformer (e.g., 60Hz 120V 120VA).
I particularly want low ...
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Using a non-isolated DC power source for a microcontroller
I am designing a frequency converter for an approximately 200W three-phase motor operating at 220VAC. I intend to use a microcontroller for control and measurements. To cut costs, I am considering ...
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1
answer
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Isolated flybacks in series to generate high-voltage [closed]
I'm considering placing isolated flyback converters secondaries in series such as the image below. I want to drive the transformers individually using synced clocks (such each transformer has its own ...
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1
answer
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MCU signal isolated and Amplified (Optocoupler+BJT+Mosfet)
I've com up with the following design.
I feel I've used too many components, don't know.
but I have some reasons for anything included in the design.
PULSE_A : some low frequency (50~1000Hz) low duty ...
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1
vote
1
answer
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Wurth transformer secondary pins on left and right side of transformer
I am looking to use Wurth Transformer 750310988 and I have noticed its pinout is very bizarre. My application is I want to float the secondary of this transformer up to 500VDC and provide a isolated ...
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3
answers
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Isolation transformers and short circuits
For some quick background and info: I'm a relatively fresh (~2y/ experience) EE in the solar field. I work in the R&D department of my company. My country operates in a 230/400V 50Hz grid.
We are ...
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3
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Understanding RS422 and choosing drivers
I want to communicate 2 MCUs using RS422. I need to have some isolation, so the driver should have 3.3V side and 5V side, isolated. All I can find in the market are half-duplex drivers, I understand ...
4
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answers
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Mixed pollution degree creepage distance
Say you need to comply with a creepage distance but you can't do it under a specific pollution degree. I had 2 scenarios where I had mixed pollution degrees:
The creepage distance is almost enough ...
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2
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How can we safely test a mains powered device?
We have small non-isolated 230VAC devices that transform mains to LEDs running at 32V, 20mA. The lights are directly connected to live, neutral and earth like a standard lightbulb would be. Since ...
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In aircraft power supply, why is the neutral not connected to chassis GND unlike household utility power?
Usually the chassis of any household equipment is connected to earth ground for safety.
Part of the culprit is neutral being connected to Earth ground. (Reasons are mentioned in this post.)
My ...
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0
answers
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Ground isolation in multichannel mixed-signal systems
There are some similar questions to mine but I have a few more specifications on top of them. Therefore, I am not 100% sure whether to ask as an iteration or present my own question on a clean slate. ...
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2
answers
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Isolation Topology in SMPS
I have been researching SMPS designs as a hobby recently and finally have the courage to build one for theoretical and practical understanding. I have chosen an isolated design looking at several ...
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9
answers
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What options exist for isolating a high power DC analog signal? [closed]
I have a high power DC signal that can range from 0-325 VDC. The source is capable of delivering up to around 150 amperes at 325 volts. I need to monitor the voltage as an analog signal by reading it ...
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What is wrong with my double pulse test Ltspice schematic? Gate pulse is not getting generated when I connect the gate driver for 800V application
What is wrong with my double pulse test LTspice schematic? Gate pulse is not getting generated when I connect the gate driver for 800V application. Any connection error?
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What does 2xMOPP really mean
I am a student and I am designing a medical device that has a type CF applied part.
I know the specifications that the applied part must comply (4kV of insulation, 8mm of creepage, <10μA patient ...
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vote
1
answer
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Isolate current flow in Ltspice using switch
I am trying to control the flow of current by the switch SW, I have used an independent current source I. However the switch is ineffective to isolate the resistor R1, because the switch is basically ...
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1
answer
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Do I need to connect a resistor at the output of an isolated DC-DC converter module?
I am using D050505S-1WR3 in my design for powering an isolated CAN transceiver. The can transceiver is the ISO1042BDWV from TI.
Below is the schematic of the power supply and CAN transceiver.
During ...
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0
answers
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How to eliminate the VFD noise affecting digital sensor reading?
I have a problem getting correct readings from a 5v digital sensor connected to an Arduino Uno board. I get correct reading until I start the VFD that drives a 3-phase motor.
The sensor reading then ...
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2
answers
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Can you draw power from the ADUM4160 USB isolator
I am developing a USB powered medical device and I am thinking of using the ADUM4160 to isolate the USB from the device.
However, there is one thing i didn't understand about the device: does it ...
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2
answers
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I keep Blowing up my i2C (ISO1540) isolator when plugging and unplugging my battery
I am using a ISO1540 to read the SMBus of some BB2590 batteries. The relevant part of the circuit is shown in the images below
The issue that I am having is that sometimes when connecting or ...
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1
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Isolation of Input signal and supply [closed]
I have this op-amp like circuit. Where the input signal is an 70V High voltage signal and the power supply is 3.3V voltage signal to a MCU GPIO.
My question is how should I isolate the high voltage ...
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2
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How to make a smart precharge circuit
I want to build a circuit that monitors the voltage at either end of the precharge resistor circuit.
Since the load will have capacitance, I should expect an RC time constant curve on the load of the ...
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0
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Connecting LVDS to oscilloscope using ferrite bead to isolate GND/SHIELD
I want to measure LVDS signals with a scope.
Will my solution work? (Shown at bottom.)
I know of other ways of doing this, but I am hoping this way is cleaner and easier.
Specs:
Frequency:~100MHz
...
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answers
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Erratic and confusing I2C behavior between ATSAMD21G18 and A89307 through ISO1644 isolator
I'm working on a BLDC driver using Allegro's A89307 controlled by an isolated ATSAMD21G18 via TI's ISO1644 I2C digital isolator. The simplified I2C connection is shown below, I omitted all the bypass ...
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Isolate modus IC
I want to isolate the RO, DI, and RE/DE pins going to the microcontroller. Can someone suggest what sort of IC would be appropriate for this application?
I wanted to use the FOD8012AR2, however, I see ...
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2
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Isolate unpowered MCU UART
I'm an EE student working on my first hobby project involving ECAD and currently I have an ESP32-C3 connected to a BM83 Bluetooth audio module via UART.
There will be moments when only one MCU is ...
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Multiple 4-20mA Transmitters from Common Referenced Analogue Inputs
I'm trying to come up with a scheme for multiple loop powered 4-20mA transmitters controlled from seperate analogue voltages, which all have a common 0V reference. My inital thought was to use an ...
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Should consumer electronics have low voltage isolation?
I am making a MCU (PIC12) controlled 230V relay system. They will be operated from 230V mains. Should I use isolation (1:1 transformer?). I would use this converter for 230VAC-5VDC (or something like ...
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2
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Removing noise from USB audio CODEC
I've created a USB audio codec using the TI PCM2912A.
The feature I use the most is the Audio Sidetone functionality, which plays back audio
from the mic so that you can hear yourself talking.
I use ...
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0
answers
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How isolate IO pins of Arduino and PSU output?
I will start by saying that I am a beginner of electronics and I don't have much experience hence I am making this post asking for advice from more experienced peopled than me.
Now that I have lowered ...
0
votes
1
answer
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Power supply of isolation amplifers
First time experimenting with a design with isolation amplifiers and I am unsure about the amplifier power supply range I need.
I need to provide isolation to measure a current between 0 and 7.4mA. ...
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Basic Wiring Help
I’m an individual that likes to tinker around with things and I’m asking for help.
I’m in the middle of a car audio system update. I currently use a basic relay as a “turn-on” switch for my ...
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Is it okay to supply two channel of isolated gate driver with same DC/DC converter?
I am planning to use NCP51560 isolated gate driver in my project. Here is the block diagram of the gate driver.
I need isolation between primary and secondary side. I don't need an isolation between ...
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0
answers
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How to get USB 3.x power but with data limited to USB 2.0 HS?
I am designing a device with a few interesting requirements. Due to power requirements, we need to draw 900mA, but due to isolation requirements, we're limited to the 480Mbps rate for our primary ...
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2
votes
2
answers
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Back calculating the input from output signal chain with an isolated amplifier and opamp
We are measuring the voltage of a charger using the below circuit with the help of an ADC present in a microcontroller.
The value of charger voltage is required for some other applications. The value ...
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