Questions tagged [isolation]
Allowing for the flow of power or information without shared electrical nodes
872 questions
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Creepage/clearance distances for regulated 320Vdc
I was tasked to do a preliminary study, to check if we can add relays for a 320Vdc distribution board (inside a subsea robot). Space is quite limited, and therefore feasibility will (partly) depend on ...
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Would this coating suit for isolating the copper side of a stripboard from outside world?
Here is an example of the bottom side (copper side) of a strip board with solder:
I sometimes need to use strip board to couple things. I then check if there's any short via continuity test. But as ...
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Converting a differential signal into a single-ended signal
I have to make an isolated voltage sensor using an isolated amplifier (AMC1300, link to its datasheet). It produces a differential output centred around its common mode voltage, \$1.44V\$ ...
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How connect MCU with non-isolated power supply to PC?
I have a smart device with ESP32-S3 Wroom as MCU. The power supply is a non-isolated offline buck switching (MP175GS). In this circuit Phase line is feed directly to the circuit as Ground and Null ...
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Linear rheostat - where lies a trick of a sliding contact with isolated wire?
This type of linear rheostat consist primarily of an isolated wire (wound around an isolated cylinder) and a sliding contact:
(Source: Linquip - Rheostat Function: The Complete Guide to How Rheostats ...
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What is the maximum potential difference between two isolated circuits?
My question is regarding the theory behind the difference in potential between two isolated circuits - both floating relative to earth. This is particularly relevant in HV applications, to prevent ...
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How can I get this optocoupler to work with both the Power Supply and 9V battery?
I'm currently working on a project where I have a circuit that needs to be updated since it needs to have some sort of isolation added to the terminal block inputs to prevent the user from damaging ...
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Can two MCUs communicate through SPI, if their supplies are from two isolated DC/DC convertors?
The situation is like this:
a common voltage source of 12V is available.
Two PCBs, each with its own MCU that is powered from that 12V, using its own isolated DC/DC convertors.
(example of the ...
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Why is it dangerous to connect a nonisolated device to USB?
I was about to make a self-powered USB device that works on its own and sometimes connects to a host. I realized my only option might be powering it with an isolated power supply. I want to fully ...
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Isolating only RS485 digital signals but not power
I am redesigning a battery powered system that communicates with other RS485 systems. The battery powered device provides the supply for the other external systems.
In the old design there was ...
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Does it make sense to galvanically isolate the control of a USB pass-through switch?
I'm designing a small board that allows, via a microcontroller powered from a separate USB port, to open/close the VBUS line between two USB ports (for example, to automate testing of USB-powered ...
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Differential reading of shunt resistance measurement in High Voltage
I'm currently trying to read the current drawn by a sensor (a cold cathode gauge) that is supplied with a High Voltage (1kV up to 4 kV) DC supply. The sensor draws very small currents in the order of ...
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What is the best strategy for measuring high voltage AC signals with microcontroller?
I have an AC waveform that can rise to about 120V peak and 10A at a variable frequency between 50-150kHz. I would like to use something like an optocoupler to scale this voltage to something logic-...
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Looking for a solution to do -1200 V measurement [closed]
I'm looking for a solution (probably with isolated amplifier) in order to do a measurement of a DC/DC output at -1200 V.
I saw that Texas has the ISO224 with differential input (negative tolerant), ...
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How to monitor AC lines with isolation?
I'm working on a project to safely monitor a 3-phase, 220V AC line with a microcontroller for power metering. My goal is to measure RMS Voltage, Real Power, Reactive Power, Apparent Power, and Power ...
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Isolated and multiplexed STM32 UART
Ok, this might be a silly question, but i'm kind of new to STM32 development.
I am designing a custom board that, among other things, it communicates with eight array of sixteen independent boards, ...
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Anyone tried small transformer to apply drive to the upper or highside? MOSFET in push pull so can use 2 N-channel MOSFET rather than a P-channel
Anyone ever tried small transformer to apply drive to the upper or highside? MOSFET in push pull say for a square wave oscillator so can use 2 N-channel MOSFETs rather than a P-channel Is it really ...
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Measuring AC mains, using scope, with isolation transformer?
I would like to measure how clean my 120V AC circuit are using an HP 1744A oscilloscope and isolation transformer. Here are the proposed configuration for the measurement before and after the ...
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Solid State Relay Photovoltaic driver not turning off - LTspice
I am trying to simulate solid state relay for 24Vac residential controls. To maintain some flexibility on design, I'm not using some integrated solution. Here a photovoltaic MOSFET driver such as this ...
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Isolate PWM of microcontroller from motor drivers
I need to design a three-phase inverter for motor control and isolate microcotnroller from power stage (gate drivers + transistors) .. look at the image
If I use LM5018 as flybuck, at the output there ...
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Isolation transformer isolation [closed]
I'm looking to get a medical-grade isolation transformer to eliminate ground loop issues in my PC/audio setup.
I understand that this type of transformer provides galvanic isolation and features ...
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What should I do to isolate an ADC from the voltage-output sensor we are measuring?
In the system we are developing, we need to get a voltage output level from a sensor on an industrial vehicle (asphalt-moving). We have a telematic box we are using as an industrial PC, that we ...
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Ground Protection Design Against Accidental 12V Miswiring
I'm working on a circuit that is primarily powered through a USB connector (5V and GND). The same system includes an I/O connector with two 12V trigger inputs and a GND reference.
To prevent potential ...
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Isolation of 600V DC 5A load without bulky relays?
I have several motors that are either 600V DC 3A, or 320V DC 5A. The motors include their own control electronics (command is provided through a separate low voltage interface, that is fully isolated, ...
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Replacing the 9V battery with two AAAs and a boost converter in my old multimeter
I have an old multimeter (MS8209) that I quite like except for one thing: it runs on a 9V PP3 battery and has a tendency of discharging it too fast even when not in use.
Since these batteries are not ...
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Connecting two isolated DC-DC power supplies
I need to connect two isolated DC-DC power supplies to simulate the operation of separate batteries. After I connect them, they should give double output voltage. This works great. The second ...
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Mixer RF-to-IF isolation
I'm having a mixer IC working in the frequency as below:
LO frequency: 4.9 GHz (generated by internal VCO)
Port1 RF: 2.5 GHz
Port2 IF: 2.4 GHz
I want to measure the RF-to-IF isolation (that means I ...
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Is it safe to ride a 220Vrms sine wave using isolated dc/dc converter?
As part of a bigger project, I'm designing a circuit that would be used to source a constant current (100uA-1mA) regardless of the output voltage. The circuit will be powered from a *5V DC source ...
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Isolation between pump and microcontroller?
I'm working on interfacing a relatively high-current pump (>1A) with a MCU. My plan was to just have the pump switching circuitry and MCU circuitry on the same board, and not take any measures to ...
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UART to Isolated RS485 port for modbus causing checksum error
I am trying to create a UART to isolated RS485 port to communicate over Modbus, both Tx and Rx LEDs are glowing together and I am getting checksum errors. The schematic is attached for reference. What ...
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Design of a compact 10W isolated DC/DC converter?
I am a beginner to converter design and just wanted some clarification before I get started about my best options for designing an isolated 10W DC/DC converter. It has to be able to step up 10V to ...
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Is there a way to pass Hipot testing between pins on the same circuit?
I am working on an adapter device that requires pretty high isolation between the pins (1-5 kV depending on which pins) per the UL spec, but we want to add a datalogging feature into it that will need ...
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How could I build an isolated PWM high power fan controller?
I have this 12V car fan and I am supposed to use it to control the temperature of a fuel cell stack with PID logic. I am using a STM32 to do so. The proposed solution looked something like this:
I ...
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Understanding resistor purpose in AC isolated measurement circuit
I am looking at isolated voltage measurement circuit: Reference Design Guide
There is a voltage measurement circuit on page 19, however, I cannot understand the purpose of resistors R65 or R50. One ...
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Shorting the Neutral and Earth after an Isolation transformer
I am working on a scale model electric project and am in the process of setting up the power supply arrangement as shown in the diagram. My plan involves shorting the neutral of the step-down ...
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Placing/switching different resistor for different sensor's pulse outputs
I am working on a software configurable resistor selection for different types of pulse inputs while maintaining isolation through optocoupler. The pulse input from sensors can be:
a) Square wave (~0 ...
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What circuit could I use to extract energy from a 4-20mA signal?
I was reading about 2-wire signal isolation circuits, which are devices that only require connecting the two cables of the standard 4-20mA signal, and they generate the same 4-20mA signal on the ...
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charging and discharging capacitors in series with no current circulating
in a circuit with three capacitors in series (or plus) how does the in-between capacitor charge and discharge if there isn't circulating current?
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N-Channel Highside MOSFET Circuit with an isolated buck converter gate schematic review
As the title suggests I have created this MOSFET circuit and was wondering if I could just get some people to review it and let me know any thoughts or concerns regarding it before I begin bread ...
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How can I measure a 0-3.3V analog signal through an isolation barrier?
I am running into an issue where I have to be able to receive an analog DC voltage that will vary from 0-3.3VDC, but I need to be able to isolate the signal before I run it through an amplifier and a ...
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What are the hazards to this DIY RMS circuit?
I want to possilby make a DIY True RMS meter that displays RMS value on an OLED screen. It would plug into a wall and hang from the outlet.
Pretty much the AC goes to a Step-Down Power Module that's ...
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How concerned should I be about the level of EMI generated by simple isolated DC-DC converters?
I'm in the early prototyping stage for a system that integrates with DMX512. One of my design goals is to make the DMX interface extremely robust. To that end I'm going to be using THVD2410, which is ...
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What is wrong with my simulation?
I am trying to design a isolated power supply with feedback control and I'm getting this error. I changed the initial timepoints and it did not simulate.
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Why does the voltage follower (Op-amp) placed in between 2 circuits as an intermediate stage?
It provides isolation between 2 stages of any circuit, I am bit satisfied with the reason due to its high input resistance.
What bothers me is , Why does the voltage follower (op amp) is called as the ...
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What protection is most suitable for a relay circuit with an unspecified load (DC coil, AC load)?
What measures can be taken to protect the relay itself and handle electrical surges and spikes in an industrial environment?
Typically, I place a flyback diode on the coil to prevent back EMF. In one ...
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Is the use of an optocoupler necessary for a relay circuit?
Given that relays inherently provide isolation and separate the control circuit from the power circuit, why is an optocoupler placed in the control circuit section of relays in industrial boards?
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Why do flyback transformers have such a large Primary Inductance when the design really only needs a fraction of that inductance?
I am working on a flyback converter design. I am new to this type of topology and I am trying to learn the fundamentals. The converter I am designing for is 120 W, with 24 Vdc @ 5 A output. The input ...
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Mitigating Single-Point Failure in an I2C Bus for Satellite ADCS [closed]
I'm working on the ADCS for a radio occultation satellite and have connected multiple peripherals to a single I2C bus. My team raised concerns about the risk of a single peripheral failure taking down ...
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Do I have to bother with isolation?
I am currently designing a device which is intended to communicate with different devices over RS232. The communication targets are mainly network switches from different manufacturers. The distance ...
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Can a pulse transformer be used for single phase 120V AC isolation?
I am looking to build a ~170V DC power supply by using a full bridge rectifier on wall outlet 120V AC. After some googling I've come to learn I really need the output to be isolated as I'll be ...
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