Questions tagged [isolation]

Allowing for the flow of power or information without shared electrical nodes

Filter by
Sorted by
Tagged with
0
votes
1answer
28 views

Bidirectional protection or isolation for generic digital communications

I am redesigning a company product, it is a product for automotive maintenance and diagnostics. Currently in the product there is a FET BUS switch to perform the interface between the microcontroller ...
-3
votes
0answers
32 views

Manufacturer replacement for isolation transformer [closed]

Item at bottom appears to be a 4 pin isolation transformer 1.8"x .75"x .4" with identical windings at 1.5 ohms on a straight laminated core. It has 120 volt input with 120 volt output. Its being used ...
0
votes
1answer
57 views

Positive-negative voltage from dual supply

I'm trying to build a low cost hifi (Hiraga Le Monstre) but I have two old computer PSUs at hand so I tried to use it as power source. The Monstre needs +12V and -12V, computer PSUs have both, but the ...
0
votes
2answers
44 views

Optocoupler voltage drop when connected to load

simulate this circuit – Schematic created using CircuitLab The inverter supplies max 25mA. The optocoupler draws 18mA. The optocoupler is supplying 1.7V to the sensor at node 1 instead of ...
0
votes
2answers
105 views

What is this Diode for?

This part of a schematic from the I/O board in the link below shows a 1N4148 diode in parallel with an optocoupler's input circuitry. What is this diode for? https://startingelectronics.org/projects/...
0
votes
2answers
63 views

DC/DC converter with 12 outputs, low noise?

I need to 5V to 5V. It might seem surprising but let me expain. I need to convert a voltage of 5V with 60mV ripple (coming from a PSU doing 120V AC to 5V DC) to say 5V with low ripple. I'm however ...
0
votes
1answer
58 views

AC line isolation on multi-level PCB design

Due to space limit I had to design the PCB in multi-level form, the top front side of the PCB is AC line and under that is DC capacitors: Is the 3mm air gap between AC line and DC capacitors enough ...
2
votes
1answer
73 views

Isolating 220V AC from low voltage DC on the PCB

Below picture is the rectifier section of design on the PCB: The space between AC and DC voltage is ~2 cm, except at the bottom that I put four M3 holes which I'm going to drill and connect them to ...
1
vote
1answer
103 views

Do small 1:1 isolation transformers exist?

I am building a Nixie clock that will be powered from 110V wall power. The design is based around having this 110Vac as the input voltage, but I wanted to put an isolation transformer inline for ...
2
votes
2answers
175 views

Switching MOSFET with isolated gate

I am trying to isolate the battery which powers the gate control circuitry from the battery which powers the hight-current load being switched by the MOSFET. Here is the basic circuit configuration: ...
0
votes
0answers
46 views

Relay module and Arduino Isolation; How to acheive?

I'm going to control a 3phase motor with an Arduino Pro mini and and a 1 Ch. relay module. In numerous articles it's been advised to separate Arduino and relay module's Vcc. For sure, the second ...
0
votes
0answers
38 views

isolation transformer in outdoor case (telecomm)

I need to build an outdoor cabinet to feed my wireless components. I have frequent atmosferic discharges and I thought to install an isolation transformer to reduce spikes from 220volt ac source. ...
1
vote
1answer
39 views

Can I isolate a onewire device using a bidirectional serial isolator?

I'm designing a board which has five onewire channels. One non-isolated, four isolated (spanning one isolation barrier rather than four separate barriers). Can I simply run the onewire bus through a ...
0
votes
2answers
80 views

3.3kV isolated heatsink for TO247 packages

I want to use some TO247 devices with an enclosure. In fact, I have to and there is no choice. The enclosure has to withstand a dielectric strength test of 3.3kV for 10sec plus 6.6kV for 20ms. All ...
10
votes
2answers
704 views

Why so few osilloscope with dedicated isolated channels?

Background: I am a junior engineer who work with testing and designing inverters for motors. I have been looking at a new oscilloscope since the one I had gave up. There are alot of Tektronix TPS2024b ...
0
votes
2answers
104 views

What type of conformal coating must I use and where must it be applied over the PCB?

I have designed the layout of a PCB that will have an unique area with crimpage terminal connectors receiving 6KV by an external wire. I have done the shortest polygon (instead traces) for 9 PCB ...
0
votes
2answers
37 views

Can I use pre-regulated PoE power safely/within specifications?

I'm attempting to design a PoE PD for fairly high-power applications; chiefly, powering/driving stepper motors. Currently, both motors and drivers run at 24V and will consume about 30W per PD. At that ...
1
vote
1answer
116 views

Ethernet with transformer

I have a schematic of Ethernet Transformer that supports POE, and 2.5GBT. I plan on using Ethernet with transformer on my PCB to connect to Network Switch. Are pin VC12 13, VC36 14, VC45 15, VC78 16 ...
1
vote
2answers
55 views

How do I safely connect a light switch button to the secondary side on a board?

I designed a special light controller board. It has a primary side that is connected to AC 230V. There are a certified AC/DC converter module and a relais, bridging the air gap between the primary and ...
0
votes
0answers
62 views

Ground Planes, 0v or GND?

I have a board that has a dual voltage isolated DC-DC converter on it. The converter takes 0 an 5v in and gives -5,0,5 v out. The 0v of the input is actual ground. Most of the PCB uses the isolated ...
0
votes
0answers
53 views

Perfboard soldering distance [duplicate]

I have a problem with perfboard, every time I made a circuit which works flawlessly in breadboard, doesn't work on perfboard. Is it because of soldering distance or am I doing something wrong? All ...
0
votes
2answers
79 views

Isolated power supply with Vout = Vin

I need to create two isolated power supplies (so that one's electrical noise doesn't affect the other) out of my 12V battery. One has to be at 5V for some logic circuitry, and the other at battery ...
0
votes
0answers
36 views

Compared to 3-port circulator, what is the use of 4 port circulator?

What is the use of 4 port circulator, compared to a 3 port circulator?
0
votes
2answers
40 views

One power supply on a digital isolator

Atmega328P provides logic signals to the AQH1213 solid-state relay to control AC load (contactor). Task: Protect the Atmega328P in case the solid-state relay fails and supplies high voltage to the ...
0
votes
1answer
27 views

Working Voltage for Basic/Reinforced Isolation (ACS712)

I'm planing to use current sense chip ACS712. I don't understand some values in its datasheet, page 2 (Isolation Characteristics). I understand "Dielectric Strength Test Voltage - 2100VAC" - that ...
0
votes
1answer
44 views

Isolated circuits: can their reference voltages (GNDs) be at the same potential?

Suppose there are two independent circuits isolated from each other. If they are isolated, the impedance is very high between them (ideally infinite) and there is no current flowing from one to the ...
2
votes
2answers
120 views

What does Ch-Ch isolation stand for regarding this context?

This scope specs mention the following inputs: I don't understand what meant by channel to channel isolation here. I made a continuity test and the input grounds of two channels are connected. I ...
1
vote
2answers
44 views

Preventing shock risk on isolated transformer secondary circuit

I fully understand that you cannot get a shock from either phase1 or phase 2 on the secondary of the isolated transformer, however you can be shocked by touching both. My question is how do you ...
0
votes
0answers
38 views

Optical Isolation of BNC trigger?

I am wondering if there is a more practical way to provide optical isolation for a BNC trigger. I am currently using the following: https://www.eagleharbortech.com/product-categories/fiber-optic-...
5
votes
1answer
161 views

Spikes in raw acceleration data from AC motor

I have an MCU with an accelerometer, tightly mounted onto an AC motor inside a production hall. Once an hour, it collects 1 sec. (Sample rate is 5000) of acceleration data for the motor and saves it. ...
0
votes
1answer
53 views

Does input impedance of an isolation amplifier or a transformer have impact on common mode to differential mode conversion?

I have a question where I can only explain it clearly by an example. It is about conversion of common-mode interference to differential mode due to overall system imbalance. I will use below two ...
0
votes
1answer
72 views

D Flip-Flops at MCU IOs

I found below PCB from a machine. It has a MCU for control all inputs and outputs and MCU inputs and outputs go through HCT374 IC to optocouplers that isolate all inputs and outputs. What is the ...
0
votes
5answers
194 views

How are electric water heating elements isolated?

From what I've seen and understood, electric water heating elements are usually copper tubes/pipes with electricity running through them to heat up the surrounding water. I'm not sure if the ...
0
votes
0answers
64 views

Flyback Isolation Transformer Alternative

I am using the mEZS84801A as a reference design as shown below. It uses the MP8007 PoE chip. I have modified and tested this PoE system successfully and my camera be powered and it can run at 1 ...
0
votes
1answer
125 views

Voltage Translation

back in electronics after 7 years and found that nothing is in my bio-disk gifted by god. now, i have a motor system that i want to make sure, no one cut the cable. apart from the 24volt motor power ...
0
votes
2answers
56 views

Can RF/switching PS noise travel backwards through a circuit through a power supply

In the schematic below there is a sensitive ADC and sensor with 4 MHz SPI lines from the ADC to a 3.3V MCU, along with a 1 MHz boost converter powering an LCD. Could switching noise generated from the ...
0
votes
3answers
111 views

isolating DC from dmx signal

I have a DMX controller using a 3 pin connector (gnd, data+ and data-). I need to connect it to some cheap chinese DMX lights. The problem is that the lights are powered over the same 3 lines using a ...
1
vote
2answers
147 views

Reverse-engineering RS485/Mechatrolink-II front-end design

I'm trying to reverse-engineer Mechatrolink-II front-end circuitry. Its physical layer is simple RS485 (with isolation transformer) running at ~10Mbps. Here is the schematic I obtained from the PCB of ...
2
votes
1answer
121 views

Massive pk-pk ripple on output using isolated DC-DC converter module

I'm having a very odd issue using an integrated DC-DC isolated converter module. As the module stabilizes, a massive pk-pk ripple is developing on both the output and the input. At first we thought ...
2
votes
5answers
1k views

Isolated audio without a transformer

I'm putting together a guitar pedal for splitting the signal to two different amps. One of the features I want to put in is a 'ground-lift'; isolating the signal to avoid ground loops between the two ...
0
votes
1answer
176 views

How does Mains Isolation work with the ACS71020 IC?

In the datasheed for the ACS71020 IC, it shows the typical application of the device in which current is passed through the chip and voltage is measured on the opposite side. I do not understand how ...
1
vote
0answers
49 views

High quasi-isolated voltage measurement

I have to measure a DC voltage and an AC voltage around 100V. I found the circuit with an AD629 and one OP177. I simulated everything in Spice and it works fine, at least in the simulation. In ...
5
votes
1answer
115 views

Barrier and slot within reduced area on a PCB

Imagine this situation in a little area of your PCB: According to the worst case and used material, I need a creepage distance = 30mm. According some tables, clearance must be 30mm. First Red banana ...
2
votes
1answer
74 views

Should isolated GND be tied to logic GND to prevent ground drift?

In an industrial environment, let's say you have an isolated interface that connects to an external sensor or device. This interface separates both logic signals to your main board as well as GND and ...
0
votes
1answer
274 views

Isolated UART communication: Which side should send the supply for the isolator?

I am in a situation to establish an isolated UART communication between two separate PCBs. The first PCB regulates and sends the required isolated power of the second one. The UART communication will ...
0
votes
0answers
64 views

PoE Design Question

I am working on a PoE project that calls for a power to be supplied to a application circuit. The application circuit requires ~41W (24V, 1.7A). I am exploring using PD70201 as the PD controller. The ...
1
vote
2answers
66 views

If my circuit is electrically isolated, do i have to worry about a polarizing effect on my sensor's output?

If I am making a conductivity sensor one of the things it need to watch out for is polarizing the water. easiest way to do this is have the output output signal of the sensor have a +/-0.2V square ...
0
votes
1answer
102 views

Can an isoSPI interface work without isolation?

Ive got a LTC6820 that I will be communicating with a LTC6811 and they both use isoSPI but all the example diagrams show the connections going through a transformers and twisted wire like this: But ...
0
votes
1answer
24 views

How to archieve induction isolation from adjacent inductors on a plane, but no isolation from inductors outside the plane

I am thinking of designing a large wireless charging pad. The idea is to have many inductors in a grid setup, where when a phone is placed on the pad it starts charging from the inductors closest to ...
3
votes
1answer
213 views

Dielectric (HI-Pot Test) Failure on Ethernet Port

We have failure on Dielectric test between Power wire to Ethernet Port. Failure was observed near 1.7kV. After test Ethernet port was damaged (Phy chip). See attached Case 1 :- Where we apply High ...

1 2 3 4 5 9