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

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0answers
52 views

Full Speed USB Isolator

Can anyone suggest a way to galvanicaly isolate a USB Full Speed (12Mb/s) signal with a solution height of less than 2mm? Parts like the ADUM3160 (link) and ADUM4160 exist but they are too tall for my ...
3
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2answers
106 views

Are IC sockets suitable for mains voltage?

I need to derive a low-voltage galvanically isolated 50 Hz signal from 230 V mains. I'll use an opto-isolator for this. I'd like to use IC sockets for all ICs in this personal one-off project. ...
0
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1answer
65 views

Earth alternative

I'm designing an industrial machine which is AC motor derived. There are sensitive analog sensors (e.g. Load cell) in the system and in the user's site, Unfortunately earth connection is not ...
0
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1answer
192 views

Oscilloscope ground and unit under test ground issue

I am working with an instrument which has a supply of 230V AC or 400V DC. AC source is isolated at the input via 1:1 transformer and DC source is a floating supply. I have a Yokogowa DL1620 ...
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1answer
78 views

Isolation for loop powered devices with limited power

I am implementing 4~20mA Transmitter that consist of a MCU, a current DAC, and an ADC for measuring an analog signal. I would like to electrically isolate the analog signal from the loop current so ...
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4answers
145 views

Relay alternatives that are silent and support 500mA+

What can I use as a silent "general-purpose" relay alternative? There are various scenarios where I will need a relay-like device that allows me to control one circuit with a separate isolated ...
0
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1answer
62 views

Need to isolate panel meters from each other?

I have a computer power supply I am planning to use for electronics work. I was planning to make a box with voltmeter/ammeter panel meters on each output voltage (3.3V, 5V, 12V, -12V). I have read ...
2
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1answer
90 views

How to decide whether or not to use isolation in a circuit that has a microcontroller and a 48V DC supply?

A potential divider connects a 48V(worst-case) battery supply and a micro-controller for voltage sensing. Is it enough if I take care of the resistor values of the potential divider so as to limit the ...
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2answers
94 views

Is it possible to use capacitor for isolation instead of optocoupler?

I designed a Buck converter which drives several LEDs. The PWM signal, which has a certain fixed duty cycle, is generated by a 555 timer IC. The circuit which drives the Buck MOSFET, including the ...
25
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4answers
5k views

Why are the high voltage overhead power lines with the same potential being isolated?

Photo #1 Photo #2 Photo #3 - A zoom of Photo #1 Photo #4 - A zoom of Photo #2 I shot these photos while travelling in a highway. In each line-group has three separate lines. I think that the ...
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1answer
825 views

Need to isolate my ammeter (measuering and powering the unit from same power source)

I have a problem and Im not sure what the best way is to address this. I converted an ATX PC power supply to use as a lab power supply I installed a digital volt meter and a digital ammeter. To power ...
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1answer
72 views

RS-485 isolation required?

I would like to confirm my understanding. Suppose I'm want to have two battery-powered MCUs inside an (unmanned) aircraft communicate with each other via RS-485. If those MCUs are powered from the ...
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1answer
133 views

Noisy Voltage Rails (Vcc, Gnd) - Noise Isolation for Automotive Circuit

I have an audio (mic, speaker) circuit that I am currently powering off of a 12V car adapter that is fed into a 10V switching DC regulator to power the rest of the circuit. I have noticed a horrendous ...
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5answers
110 views

How do metal cases work with connectors & isolation?

I have troubles understanding how do metal cases behave in some cases. Case 1: I made passive attenuation box for amplifier(basically L-pad resistor), simple configuration: Amplifier => attenuation ...
4
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1answer
79 views

ADuM1301 digital isolator - PCB layout question

We are using the ADuM1301 digital isolator in one of our designs. The PCB layout section from the data sheet states: In applications involving high common-mode transients, care should be ...
1
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1answer
117 views

Ground coupling a high voltage source with the A_GND and D_GND

I have a device that measures the current in the mains through a 0.01 Ohm 20W shunt resistor. The voltage across the shunt is amplified by a op amp and feed into a uC's ADC for farther calculations. ...
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1answer
110 views

What is the difference between TO-220F and TO-220FP cases?

Google search results implies TO-220FP to be full-pack case. Wikipedia says that TO-220F is full-pack case. Farnell categorizes TO-220F and TO-22FP differently. I'm confused. What is the difference ...
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2answers
57 views

Passing control voltages to multiple isolated power supply channels

I'm designing a programmable bench power supply (PS) that has multiple isolated channels (each powered by a separate transformer winding). I like the idea of isolated channels so that multiple ...
4
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3answers
1k views

home brew isolated oscilloscope lead

The ground clip for an oscilloscope lead is normally connected within the instrument to the power supply earth, and there are surprising circumstances where this could matter. The situation is very ...
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2answers
103 views

How to make a RF Additive Mixer for two inputs in same frequency band?

One of the most common designs for a SSB modulator (phase shift method) involves an additive mixer as the very last stage. Here is a block diagram for reference: This additive mixer must provide ...
4
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1answer
122 views

Do I need to isolate the output voltage feedback in SMPS?

I almost finish with my Half-Bridge SMPS design. I'm now designing the output voltage feedback to the controller stage. The controller stage drives both MOSFET transistor through an isolation ...
2
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4answers
247 views

What is an appropiate way to isolate a DC signal?

The question might sound kind of funny, but I'm unsure how else to word it. So... Pictures!! Currently, I have a setup like this: simulate this circuit – Schematic created using ...
3
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3answers
266 views

Ways to isolate DC power source

I need to isolate my circuit from the power source of 5V dc. Since this is for medical use, and the device is powered by USB, the isolation needs to be at least 4kVrms, 5mm clearance, 8mm creapage ...
2
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1answer
108 views

When an isolation transformer is not enough? [closed]

I work for a fairly large church and we have powered line array speakers that do not have attenuators in them. Over time a ground loop occurred from the stage lighting causing a very distracting ...
0
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1answer
80 views

Isolating polarities on a series wired battery bank

Can anyone, with 100% certainty (that means you know what you are talking about) tell me how to "isolate" the positive from the negative posts electrically in one direction so I have a true 'positive' ...
0
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1answer
102 views

1:1 isolation transformer fuse on secondary side - an option?

We sometimes use an old self build 1:1 isolation transformer (150VA) in our company to isolate devices under test. It is equipped with a primary 500mA fuse (slow) in series with a on/off switch. ...
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2answers
55 views

Separating / Isolating the circuit blocks

I was designing the circuit of a superhet receiver, block by block. Needless to say, my concern is how would I separate the various blocks. In other words, how would I interconnect the blocks ( not ...
2
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3answers
166 views

Galvanic Isolation with Voltage Equalization?

I need to equalize the ground voltage between the input and output of an isolated DC-DC power supply while still maintaining galvanic isolation. Is there a way to do this? The reason I need this is ...
3
votes
1answer
202 views

Are the non-metallic colored heat sinks of transistor packages electrically isolated/nonconductive?

When I look at transistor packages, I see two different heat sink types. One type is in metallic color, the other type is black plastic colored. I read datasheets of some components, none of them ...
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2answers
107 views

Isolation Transformer Safety

I recently purchased an armax 230 ISOTRAN Model 1521. I can’t find it on the web anywhere, and from what I understand it is an isolation transformer that takes in 115 VAC and outputs about 210 VAC. ...
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3answers
69 views

Low power Analog signal Isolation

In my project, the current budget is very tight. With less than 1mA, I have to isolate sensor's signal voltage and be able to measure it with ADC on the other side of the isolation barrier. What I ...
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vote
4answers
323 views

Powering an AMC1200 Isolation Amp

I need to measure a very small current at the high-side of a circuit. The high side is at 3000VDC. The measurement needs to ultimately be in the form of a signal with a peak of no more than 5V, so ...
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1answer
195 views

Isolate two Arduino analog inputs

I have a stereo VU meter. (Audio in on Arduino pins A0 and A1 and GND to common GND also 32ohm resistors going to GND on A0 and A1 to simulate coming speakers) Now my problem is software architecture ...
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1answer
303 views

Isolating PWM From H-Bridge

I have a H-bridge based on FAN7392 drivers. This bridge works at 350VDC to output a approximately 240V 50Hz waveform. This circuit is isolated from rest of the board and I would like to maintain the ...
4
votes
1answer
270 views

How do AC and DC hipot tests compare?

Suppose I have a DC/DC converter, Recom RPP30 for an example to hand. It lists an isolation voltage of 3000 VDC. How does this translate to an AC isolation voltage? Would this be equivalent to 3000 ...
3
votes
2answers
479 views

Why DisplayPort cables must isolate the power pin?

I've been investigating why my 2560×1440 DisplayPort monitor and my mini-DisplayPort MacBook Air don't play along, and, it turns out, this is likely due to a wire in the cable that connects the two ...
0
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1answer
62 views

Should AC voltage supplied to an external device through a relay be electrically isolated from the main power source of the enclosure?

Given a power supply in an electrical enclosure powered by 120 VAC. An I/O device will trigger a relay with a 24 VDC control. The signal from the I/O device will enable the relay for a set duration. ...
8
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3answers
881 views

Are there any disadvantages using magnetic couplers instead of opto-couplers?

I'm trying to find the disadvantages of using magnetic couplers versus opto couplers (1). I'm deciding which of the two I should use to create a galvanic isolation between two PCB's that are going to ...
1
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1answer
101 views

What is this Circuit's function? Does it involve Isolation?

My question is: Does this circuit isolate the "X Volts" lines from ground (1) If not, how should I implement an opto-coupler to provide isolation between the data lines ("X Volts") and ground? ...
2
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1answer
103 views

How to work out or calculate this circuit?

I'm not an engineer, I understand a lot but I fail to understand how it works and how to calculate this for a 24vdc input:
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2answers
190 views

Isolation of CAN-High and CAN-Low signals [closed]

I have to isolate the signals CAN-High and CAN-Low on a CAN bus. Is there an isolated CAN repeater (something like IXXAT's CAN-Repeater - 110 × 75 × 22 mm) which would be ...
0
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2answers
116 views

How do I leave electrical connection of heat-sink body?

I usually see that some heat-sinks have thick pins to solder on the PCB, and I'm going to use one of them. Since they are going to be soldered on the PCB, the question rises in my mind about their ...
12
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3answers
4k views

Cellphone charger has no transformer?

I opened up a really tiny mobile phone charger I have, to see how it is designed. The entire "charger" is integrated into a small 2-pin mains plug, 1 x 1.25 x 0.5 inch, that has an USB socket for the ...
11
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2answers
1k views

Why AC points on PCB are separated by a hole

I want to find out why, in professional PCB's, they separate between the AC (220 VAC) points on the PCB with a hole in the PCB: Is it for more isolation between the AC lines? Is leaving a distance ...
2
votes
3answers
203 views

I2C isolation; 3kV

I am working on a high-side current sensor, where the high-side is around 3kV. I have come to the conclusion, with some help from you kind folks, that it is best that I float the majority of my ...
1
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0answers
142 views

How to isolate DS2406 switch from mains? [closed]

I would like to use a DS2406 1-wire control chip to switch a mains load. Isolation is required and I would like to use the 1-wire supply. There are no power supply at the remote end, only 1-wire ...
3
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1answer
166 views

Proper power design for a USB device

I'm designing a USB device that I want to be powered eintirely from a wall wart and have a couple questions concerning the power connections and ground loops. 1) If I connect the USB GND pin to ...
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2answers
178 views

Isolate wires soldered on PCB

I'm soldering some cables on a PCB. They are are stranded, so I've first apply a bit of soldering on them and then solder them on my pcb. The problem is, there's on some a bit of exposed copper on ...
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1answer
98 views

How can I isolate a servo in this circuit [closed]

I have a PIC which I am using to control a servo, I have a 5v supply for the PIC. I wish to isolate the servo from the PIC as the noise the servo creates can cause the PIC to malfunction. NOTE: I only ...
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0answers
471 views

Can You Drive Back-To-Back MOSFETs (aka a Solid State Relay) Without Using An Optocoupler?

I was wondering if there was any way of driving back-to-back MOSFETs (with their sources and gates tied together as shown in the following image) without using an optocoupler? The reason is that ...