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Questions tagged [isolated]

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ESD on two different materials

I am conducting ESD testing on two types of materials with a setup that closely follows the 61000-4-2 standard. We have incorporated both isolation material and a ground plane into our setup. When I ...
DRF's user avatar
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1 vote
1 answer
36 views

Measuring Line to ground voltage of an ungrounded, isolated output (secondary) in an single phase 400/24v transformer

So we have this electrical control panel in which we have a 24v dc and a 24v ac circuit both. The 24v ac is coming out of a 400/24v transformer. The transformer primary is being fed from a 3-phase ...
Aamir Awan's user avatar
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0 answers
54 views

Isolation transformer isolation side earthing best practices

I have been told I need my equipment to be isolated, but I want to make sure I fully understand when an isolation transformer is no longer isolated. The equipment I have clearly has an earth ground, ...
JCoder's user avatar
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1 vote
2 answers
102 views

Isolated negative Vdg on MOSFET

This is probably crazy, but: What would happen if I apply a negative voltage between the drain and the gate of a MOSFET (or positive from gate to drain), assuming that this voltage comes from an ...
Valentin Richard's user avatar
2 votes
1 answer
266 views

Is this the correct isolated circuit to control a relay output from a Raspberry Pi GPIO?

I am making a circuit for an optically isolated relay output controlled by a Raspberry Pi GPIO pin. I am not sure if this is the correct way of doing it. Can someone please help me out on this? Edit: ...
Praveen's user avatar
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3 answers
378 views

Safety of grounded and isolated AC in medical systems

Introduction I try to make more sense of safety and reliability of grounded and isolated electricity. I divided the problem into 3 stages: Power-transmission line Household electricity Electrical ...
M lab's user avatar
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4 answers
140 views

Isolated voltage measurement circuit or sensor

Which circuit or sensor can measure a voltage range of 24 V DC (the power supply for a motor)? The circuit is fully galvanically isolated from the ESP32 used. Does anyone have any ideas on how to ...
Yukta Sanghvi's user avatar
1 vote
1 answer
77 views

Can I use isolated power supplies by connecting the input gnd and output gnd together?

I need a converter module that outputs +15 -15 Volts to feed the opamps. My input voltage is 24V. I found that UWE1215S-3WR3 for this application. UWE1215S-3WR3 datasheet I know that normally the ...
Electronx's user avatar
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0 answers
30 views

Working (real) voltage offset of isolated DC/DC modules

I do not see in 95% maybe cases for isolated DC/DC modules such a parameter like "Maximum-rated isolation working voltage" but see something like "I/O isolation 5000 VAC rated for ...
Pinus's user avatar
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0 votes
2 answers
67 views

How to control unrelated circuit with a transistor?

I recently hit this issue that seems to be too complicated for google to find results for. Is it possible to control a different circuit with a transistor from a separate circuit? Below is a ...
Athwale's user avatar
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1 answer
54 views

How to tell if buck converter outputs are isolated? [closed]

I'm looking for a cheap CC CV buck converter with separate grounds. How can I determine which converters have isolated outputs and how can I find such modules? I know sites like ebay and the likes are ...
php_nub_qq's user avatar
2 votes
2 answers
318 views

Isolated power supply: Protective earth connected to secondary ground

We are developing a device that contains an isolated AC/DC power supply, from mains voltage to 3.3V. A colleague wants to connect the protective earth (chassis ground) to the secondary 3.3V side ...
Blackfield's user avatar
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0 answers
22 views

Changing grounds during start up

We have a system with a CANBUS controlled Battery Management System (BMS) and a PCB with microcontroller. The BMS provides 12V and an isolated CAN ground at all times, but naturally only supplies main ...
Sylvester's user avatar
0 votes
1 answer
44 views

About isolated Power Supply Remote Control Mode

I am using mean well SCW12 series isolated dc dc smps power supply module. The thing that confuses me is the working principle of the r.c pin. (PowerON: R.C. ~ -Vin > 4VDC or open ; Power OFF: R.C. ...
Electronx's user avatar
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2 votes
2 answers
93 views

Is that good application paralleling power copper pours on PCB for heat dissipation and connect with via?

I am using isolated SMPS power module in my PCB layout. I found good examples about layout here. https://www.powerctc.com/en/node/5139. I have completed routing the isolated SMPS power module from the ...
Electronx's user avatar
  • 756
1 vote
1 answer
223 views

How to use isolated amplifier to measure voltage

I want to read the cell's voltage with a microcontroller, but the cell does not share the same GND with the microcontroller. I want to keep them separate. I read some suggestions for this problem, and ...
Alex's user avatar
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1 vote
0 answers
86 views

Can I connect the isolated grounds of multiple DC/DC converters together?

I am working on a project that involves using isolated DC/DC converters to power gate driver ICs that will then switch on/off IGBTs. I have 9 DC/DC converters that will power 9 gate drivers each that ...
Luis's user avatar
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0 answers
106 views

What are the correct signal ground connections in an RS485 system with a shared ground on motor drivers?

I'm in the process of designing a motion control system using RS485 and whilst we've generally made things work in the past with a more trial and error approach, in the interest of doing things right ...
Will Laslett's user avatar
0 votes
1 answer
56 views

How come I'm not getting the same output at the EAout, with the unity-gain buffer EAOUT output follows the +IN input

The EAout pin does not output the same signal as +IN, the signal is coming from a voltage divider after full bridge rectification
S_D's user avatar
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1 answer
130 views

Using isolated gate driver for switching loads sans MOSFET

I am trying to simplify my circuit and use a single multi channel part for both driving high current MOSFETs and directly driving a much smaller inductive load without a MOSFET basically as a digital ...
Nick Bur's user avatar
1 vote
2 answers
99 views

12 V isolated DC-DC converter connection

I have a question about a 12 V to 12 V isolated DC-DC converter. I am trying to connect a Bluetooth adapter to my old Becker radio, but I got some annoying noise when it was connected. It turned out ...
nasty12312345's user avatar
1 vote
2 answers
421 views

Decoupling Capacitor DC/DC

What's the physical base of 1nF capacitors (CY) between isolated grounds of DC/DC converters?
Erick.87's user avatar
1 vote
1 answer
83 views

Serial connection of isolated DC/DC supplies

I need isolated 60VDC and I am struggling to get one that can provide enough current (2A is needed). It seems to me serial connection of 4 supplies that deliver 15VDC can be a solution. What can be ...
Kurt Müller's user avatar
0 votes
2 answers
114 views

In what conditions can a DC isolated power supply generate a higher voltage at the flyback transformer's secondary side?

We have designed a passive PoE isolated power supply using a TOP268 converter. We are converting 48 V DC PoE input to 12 V/1 A output. This 12 V output we are feeding to a step-down power regulator ...
Mohit's user avatar
  • 11
3 votes
2 answers
613 views

Flybuck converter at high power

It is said that the flybuck topologies are cheaper than the flyback topologies. This is due to the fact that there is no need to have an optocoupler, the regulation is said to be simpler and probably ...
Jess's user avatar
  • 2,478
2 votes
1 answer
105 views

Isolated RS485 without specialized IC

I'm looking for replacement for ADM2587E. This is ADM2587E: Can I just use cheap, not isolated RS485 transceiver like MAX485 connected to microcontroller TX, RX, DE/_RE via optocouplers and power it ...
Kamil's user avatar
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0 votes
1 answer
104 views

Eagle I can not change the isolete value of bottom Ground polygon

well this is my PCB design with Eagle Autodesk. Ground polygon looks perfect with Isolate value 0.8128 [mm] on Top. but this value can not effect bottom polygon Why? How can apply 0.8128 isolate ...
mehmet's user avatar
  • 1,139
1 vote
1 answer
492 views

XL6009 and isolated output

I want to make an isolated DC to AC power supply, with the XL6009 circuit, and I don't know what role "Cdc" have in the circuit. Can I take it off? My power supply is powered at 5v DC and at ...
Miau's user avatar
  • 55
1 vote
1 answer
642 views

HVAC 24VAC backfeed prevention [closed]

I have an HVAC system with a powered open/powered closed supply damper, Ultra-aire 120 V dehumidifier and ventilation damper that is powered to open. I have everything wired up and it is working, ...
micron's user avatar
  • 21
0 votes
1 answer
142 views

Voltage regulation, 5V +10% to 5V

I'm making an isolated communication/power module PCB, and I came across a problem that the B0505 isolated DC-DC converter has poor output regulation (+15% to -7.5% under load), and my HCS-LSP hall ...
Oxmaster's user avatar
  • 157
1 vote
2 answers
754 views

Can I use common mode power line choke as 1:1 transformer in isolated buck-boost switched mode power supply at 20 - 100 kHz?

I'm planning to build a multi-output power supply that allows output voltages between 0 - 30 V and currents below 5 A. The idea is that I will purchase a number of 30V 5.3A power bricks (unknown if ...
juhist's user avatar
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0 votes
0 answers
29 views

B2424S-2WR2 supply current

Anyone already use B2424S-2WR2 ? I want connected it with TSR 1-2450 but still confuse will it can supply good current to TSR 1-2450 here the schematic
Rizkis Walker's user avatar
3 votes
1 answer
420 views

What is the purpose / function of these bypass capacitors in this Isolated Supply EMC Filtering circuit?

I found this EMC Filtering circuit in the datasheet of the RFB-0505S DC-DC Isolated voltage regulator. What is the purpose of C2 (1nF) and C3 (2.2nF)? I don't understand why they are suggested. Is C3 ...
scottc11's user avatar
  • 433
-1 votes
1 answer
135 views

Do I need to regulate the output of a forward converter?

I'd like to know if a forward converter will maintain a nominal output on the secondary side. For example if I wind a powdered iron toroidal core with 1:10 turns ratio, the 1 being the primary, and I'...
BELSmith's user avatar
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0 votes
1 answer
313 views

Isolated Current Shunt Amplifier

I have twenty isolated power supplies (around 40 V max) which need to have their current draw sensed and monitored. I'm currently using a TI INA138 current sense amplifier, which sort of works. ...
Dan Twining's user avatar
0 votes
1 answer
2k views

Noise from a relay during switching

Is okay to have a load use the same ground as the coil supply of the relay. From my understanding relays do sometimes 'bounce' when switching from N/C to N/O. This inturn can then create some form of ...
JoeyB's user avatar
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0 votes
3 answers
2k views

Isolated grounds in power supplies

Can someone assist me with understanding why some power supplies for instance DC to DC power supplies sometimes use more than one ground in their circuit? I have noticed that also some components on ...
JoeyB's user avatar
  • 2,389
1 vote
2 answers
681 views

Powering isolated RS485 over CAT6

I'm creating an RS485 network where data and power will be transmitted over a 23AWG CAT6 U/FTP cable. Two twisted pair conductors will be 36V and GND respectively, another twisted pair will carry the ...
Max's user avatar
  • 547
2 votes
4 answers
1k views

Measuring high voltage with isolated ground

I'm trying to measure the output voltage of a constant current LED driver that ranges from 140VDC to 170VDC. I'm using an STM32 MCU which is powered by a separate external power source to measure the ...
Max's user avatar
  • 547
0 votes
1 answer
49 views

AMC1200BDUBR Gain is 4 instead of 8

I want to measure grid voltage with AMC1200b. I used a resistor voltage divider and I lowered grid voltage from 110v(rms) to 110mv(rms). I fed the 110mv(rms) signal to AMC1200b (for the first side of ...
ReZa Alavi's user avatar
1 vote
0 answers
558 views

Confusion of the working principle of Isolated SEPIC converter

I am a bit confused about the current flowing in the magnetizing inductance L_m when the switch is off. I am reading a book(Erickson & Maksimovic, Fundamentals of Power Electronics, 2020), ...
Martineo Pang's user avatar
0 votes
2 answers
83 views

Can C3 in the schematic be polarized?

Here's the data sheet if it helps. https://www.cui.com/product/resource/pdqe15-d.pdf The DC\DC converter is an isolator unit so the left part of the circuit doesn't us a traditional GND, which leads ...
DRC's user avatar
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0 votes
0 answers
42 views

In the given circuit would CY2 connect the grounds leading to non isolated circuits?

Here's the datasheet for the part being used https://www.cui.com/product/resource/pdqe10-d.pdf I'm using this part to isolate different parts of a circuit. The schematic above is the recommended EMC ...
DRC's user avatar
  • 107
1 vote
2 answers
83 views

flyback RCD design

the equation is used to calculate the power of RCD, I know this power is from leakage inductor the inductor energy can use 1/2Li^2 to express, but I don't know how to get this document equation. Can ...
Jitter456's user avatar
  • 575
1 vote
6 answers
1k views

Electrically isolate bottom side of a PCB

I have a 4-layer board with no parts on the bottom side, the bottom-side solder mask fully covers all vias. I want to stick the board with a double-side adhesive foil on the metal bottom side of a ...
user3531827's user avatar
0 votes
1 answer
61 views

Verifying electric brake current with opto-isolated feedback

I would like to find a way to sense (or detect) current through an opto-coupler. This opto is used to power an electromagnetic brake, but depending on the type of brake the current through it can ...
Alex Er's user avatar
  • 111
0 votes
1 answer
519 views

EMI shielding ground and isolated DC/DC

Given an isolated DC/DC converter, such as Traco TMR4. The GND fill, and internal GND layer(s) would be referenced to the -Vout pin. The TMR4 has an application note showing a fairly typical EMI ...
Arcatus's user avatar
  • 1,845
1 vote
3 answers
1k views

AC mains isolated voltage measurement

I am looking for a AC mains voltage measurement circuit for my controller which has to be isolated. There are a lot of circuit using step down transformer, but all of them are too large for my project....
Tom's user avatar
  • 65
0 votes
1 answer
128 views

Isolated dc dc converter

What is the best way (low cost) to obtain a 5v isolated output from 24v batt? The 5v isolated is only for power transceivers so not to much current output is required
Marco Semenzato's user avatar
0 votes
1 answer
469 views

RS485 isolated circuit - forgot connections. Will this work?

below is my schematic for isolated RS485 section. FYI B0305XT-1WR2 is used for power isolation and ISO1500DBQ as transceiver. As you can see I forgot to place GND & GND_RS485 connections at pins 2 ...
ProPlayerMaxUltra's user avatar