Questions tagged [current-rating]

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votes
6answers
359 views

Cables with different cross section having the same max allowed current?

I was looking to buy a power cable recently and my eye caught this weird fact. Look at these two cables: https://www.savio.net.pl/en/product/savio-1-8-m-schuko-m-power-cable-iec-c13-cl-138/ https://...
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1answer
46 views

Power Supply Transformer Advice

So I'm trying to fix the power supply for my espresso machine. I've determined that the transformer is likely the problem (no continuity across the primary coil). The OEM transformer (encapsulated) (...
3
votes
2answers
280 views

Create Transformer Center-tap From 2nd Secondary

After ordering this 200VA, 32V transformer, I realized that it doesn't have a center tap on each secondary, which I need to have. (duh on my part) So I want to use 110V across the 220V primary leads ...
2
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3answers
76 views

Where do AC/DC power adapter manufacturers get their high amperage (>12.3A) barrel plugs? [closed]

I was looking to swap out a barrel plug on a spare Dell 240 watt AC/DC power adapter to avoid having to purchase a ~$80 replacement with the correct plug. I went off to Digikey and Mouser in search ...
2
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1answer
1k views

If a device is rated at 12 V/80 mA what does that mean as far as the length of time that it will draw 80 mA?

I have an electromagnetic device designed to hold a fire door open until either the circuit is cut or the building's electrical supply goes out. At which point the door is released and will close. It ...
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1answer
300 views

What factors do I need to consider when selecting an inductor to use in a circuit with the MT3608?

I am trying to use the MT3608 chip to boost the power output of a 3.7V lipo battery from 3.7V to 5V, which will ultimately power an ATMEGA32U4 chip. Below is a picture of my circuit where I have ...
3
votes
2answers
621 views

Potentiometer overheating - is it due to current rating?

I need to get a pump running at different speeds so I ordered an electric motor, a potentiometer and a power supply adapter. I put them all together and they worked, however the potentiometer got ...
1
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2answers
693 views

Current Rating of a device (how does this change when changing the voltage)

Let's say you have a device that is rated at the following: 550 amps @ 12Vdc (heat) Max Voltage = 48Vdc (insulation material max voltage rating) I am mainly concerned with the heat, we could ...
0
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2answers
129 views

What could be the output current rating of the following shunt regulator?

I am trying to solve the 2013 paper set by ISRO for electrical engineers. I wanted to verify if my answer to Question no 18 is correct. So \$I_L\$ is being drawn out of the circuit shown. Since the ...
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2answers
264 views

Current rating for busbars

How does one go about calculating the current rating of self produced busbars? Store bought wires are a lot easier, as they have the derating factors for parallel wires and ambient temperature readily ...
0
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1answer
32 views

Does Switch current rating matters if its connected to ground wire

I am designing a pcb with an SMD switch. Usually my circuit needs 200mA peak current. But I am putting a 25mA rated switch on the ground line. Now according to my knowledge if I was placing this ...
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2answers
336 views

Less voltage more amp? switch characteristis [duplicate]

I have a question regarding switches, relays etc Ex, if I have a switch rated for 24v 0.5a, can the contacts then safely handle 12v up to 1a? Because the power passing the switch is the same? Or ...
1
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2answers
363 views

How to guess voltage ratings and current ratings in capacitor and inductor?

I have a list of values of capacitors and i also know their material types! But i don't know how to figure out their voltage rating? "Ratings have been removed in the capacitors for this purpose" ...
0
votes
1answer
589 views

Does a VSR current rating affect the size of leisure batteries that it can charge?

(Apologies if this is a silly question, I don't do much electronics.) I'm converting a van into a camper. I've bought three 12V 95Ah AGM batteries (which, incidentally, will be hooked up to a solar ...
5
votes
1answer
1k views

Why do the normally closed and normally open relay contacts have different current ratings?

Please refer to the image below: Taken from the datasheet: http://www.songchuan.com/db/pictures/AdminModules/PDT/PDT090410001/201191913495127935.pdf
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1answer
2k views

How to find step down transformer secondary output current rating?

I have obtained a small transformer with 7 windings, a 220V and 6 other individually isolated low voltages. How can I find out the current rating for the lower voltage windings? I was told these used ...
6
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4answers
5k views

How to determine the nominal current of an LED?

I salvaged the LED disk from a defunct LED light bulb. (The problem was an arced transformer, the LEDs are intact.) It has several unmarked white SMD LEDs soldered on it: 5 lines parallel, with 3 LEDs ...
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0answers
540 views

Can a 12V 7AH@ C20 battery support a motor having load variations form 1-10 Amps?

I want to know what is the significance of C5, C10, C20 rated 7AH Battery to drive a varying load 12V DC Motor. Is it possible for a C20 Battery to power the motor for atleast 20Mins or so if the ...
2
votes
1answer
443 views

How to calculate the maximum current rating of an ammeter manganin shunt?

I want to make a shunt for an ammeter using a manganin wire. I don't know how to chose the wire diameter for the desired current. For example, my shunt will have 0.05 ohms and it must withstand 5A for ...
3
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5answers
3k views

Why do some wire gauge ampacity charts state vastly different current ratings?

This is a question that I've had for a while but have somehow managed to go without asking. Looking at all the wire gauge ampacity charts online, some of them appear to provide vastly different ...