Questions tagged [fuses]
Questions regarding physical fuses. A fuse is a safety device consisting of a strip of wire that melts and breaks an electric circuit if the current exceeds a safe level. PPTC, PTC, and Polyfuse questions should use the Polyfuse tag. Please keep in mind that repair questions are typically closed if not within the scope of the site and FAQ.
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Are these the correct fuses?
I am trying to repair an air fryer with a failed internal fuse.
Here's a picture of the fuse:
I want to know if this is a suitable replacement.
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Is this part a 1.1A 0805 self-recovery fuse?
I bought this online, It should be 1.1A 0805, but is it ? The pakage size is correct, Its 0805 but the value, I have doubts!
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What fuse can I use to replace this old glass tube fuse?
With what can I replace this old glass tube fuse?
Original fuse: glass tube fuse with the engravings "UEC 10A."
It is from a industrial motorized device perhaps 15-20 years old from Japan.
I ...
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What slow fuse should I get?
I had a fuse go in our old microscope. It says 125V 3 amperes on the top of the fuse. It is a slow fuse. This is what the broken one looks like. I have not been able to find the same part in my ...
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Replacing fuses on inverter PCB
I have an inverter that stopped working (after the 12 V DC power source was repeatedly connected and disconnected through a relay with a false contact). When I opened it, I saw some fuses that are ...
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3
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Modified microwave oven transformer makes fuses blow upon powering without load
I have a microwave oven transformer (MOT) from an old microwave that I want to use as a step down transformer. Unfortunately, I destroyed the primary coil when removing it so I made myself a new ...
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Maximum load capacitance and rating for fusing for bridge rectifier
I'm looking for a replacement for an old bridge rectifier and I've found one (Vishay B80C1500G), but I'm curious about two parameters of the bridge rectifier:
Maximum load capacitance
Rating for ...
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Fuse tap direction. Please help me understand which way is correct
I have a car fuse tap and was wondering if it is directional and why?
Please help me understand from bottom 2 variations which direction should I install it and why.
Thank you!
Fuse Tap:
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202
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Should I chooses fuse with a lower value than nominal?
I have found this sheet about fuses and it makes zero sense to me - a fuse rated 30A will only blow at 50A?
Does that mean I have to choose a lower value, like ~20A for my <30A application?
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Can I use PPTC fuses instead of light bulbs to make an adjustable A.C. current limiter?
In Adjustable-ac-current-limiter-for-output-of-variac-for-safe-circuit-testing, I asked about alternatives to using incandescent light bulbs to make an adjustable A.C. current limiter. The challenge ...
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What is the current industry practice regarding the impact of current-limiting fuses on arc flash calculations?
Suppose you have a panel. The arc flash incident energy for this panel is computed based largely on the available short-circuit current (SCCA) to the panel, and the protective devices upstream of the ...
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Replacement fuse specification
I have a lighting fixture with a blown fuse on the PSU PCB. The blown fuse fitted was a "T3.15AL250C" 932 (red-coloured) box fuse. I replaced it with a "T3.15A 250V CQ MST" of the ...
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Would a 20A, 12v fuse be functionally identical to a 1A, 240v fuse?
1Ax240V=240W
20Ax12V=240W
Assuming both fuses are of the same type, would they be interchangeable?
I'm aware that 240v fuses may not exist. I'm assessing the viability of substituting a 250v fuse with ...
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4
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How can I protect a 12 V, 5 A circuit from high current due to short circuit condition?
How can I protect a 12 V, 5 A circuit against high current due to short circuit?
I have tried resettable fuses but they do not work as expected. I have tried MF-USML300/12-2. In actual application (...
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Overcurrent protection (at 4A 100V)
On the PCB I'm designing, the total power consumption might be as high as 86W (including output power), with supply voltage between 18 and 75V DC (it is OK not to allow full output power bellow 22V). ...
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Can I use a 3 A fuse to a 13 A wire?
I made an extension cable from a 3 A cable because I wanted a thinner cable.
The plug came with a 5 A, 240 V fuse but I replaced the fuse with a 3 A, 240 V fuse.
If the appliances I use take more than ...
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PSU input fuse selection doubt, related to buck DC-DC converter
Suppose a buck DC-DC converter, specified for 10~60V input range, that in the worst case it has 80% efficiency (0.8), that at its output, with 5V, the average current is 3A, but that peaks of up to 5A ...
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Placement of inrush current limiter and inductor filter with respect to fuse
I'm trying to assemble the input circuit of this power supply: https://gaptec-electronic.com/datenblaetter/5ACFEW_3.pdf
The recommended input circuit is as follows:
For space management reasons, it ...
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How to size a fuse to protect a component?
I am trying to verify that I have correctly understood how to size a fuse to protect circuit components.
Lets assume I have a resistor model series that can tolerate 60W for 1 ms according to the ...
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Obsolete DMM fuses - what are safe substitutions?
I have two DMMs that need new fuses to measure current.
The first DMM is a small Radio Shack cheapie that wants a 5x20 mm 250V ceramic fast-blow 0.315 A, the second DMM is a Triplett 1101 A (still a ...
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Multimeter fails to measure current but voltage, resistance and continuity measurements work fine. Is the fuse blown?
I am trying to measure the current of a pretty simple circuit consisting of an LED, resistor and 9V battery. As I said measuring the voltage, resistance, continuity works fine but the current ...
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453
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Battery fuses breaking capacity: main and accessories
I am looking to size several fuses' breaking capacities on a battery circuit.
Let's consider F1 = 300 A; F2 = 20 A; F3 = 40 A.
Given the battery is high-power and can output several kAs, the main fuse ...
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84
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Is it safe to briefly short the secondary of a power transformer to measure the maximum fault current at the primary?
I have a bunch of salvaged step-down mains power transformers (220V-240V primary voltage at 50Hz), with powers ranging from a few VA to maybe 100VA. In order to use them safely in my projects I need ...
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Can I get the current rating of fuse wire from its gauge?
I've got a very old piece of equipment with no manual/documentation/labelling that uses plan bare fuse wire in several locations in the wiring, that I'd like to replace with standard cartridge fuses.
...
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What does a table of "breaking capacity" values mean in a "slow blow" fuse? (And translating fuse markings...)
I need to get a 1.6 amp, "slow blow", 250V, 5x20mm fuse for a piece of equipment.
The ones I bought in the attached picture seem to be the correct ones (according to the store). Sorry for ...
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Can I do a parallel connection with fast fuse T4A and simple incandescent bulbs on 220V?
I want a light bulb to light instead of a fuse blowing when the circuit is short-circuited.
What will happen if I put a 0 A light bulb in parallel with the 4 A fuse?
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446
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Help identifying a fuse(?)
My vacuum cleaner has a motorised brush head that's just packed in. I've taken it apart and found what I think is the problem part. The part labelled 'F1' on the silkscreen, so presumably a fuse, has ...
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Identify fuse end cap marking "LF"
Does anybody know what this "LF" pair of characters mean on the fuse end cap?
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98
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BMS balance lead fuses for 2A active balancer
I am building a 16S pack of lf280k LiFePo4 cells. I will be using JK BMS capable of 2A balance current and will be connecting to each cell with wires with fuses. I assume 3A will be sufficient.
Do I ...
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Should my 50mA fuses be blowing up?
I am running a PCB that requires me to use a 50mA fuse (F0402G0R05FNTR,) but my PCB consumes a peak current of about 60mA during operation for 24ms every 327ms at 125 Celcius application as shown ...
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Current limit in low-power device
I have a circuit that is powered up by six AA batteries. I am applying for safety certification, and one of the requirements is that the max. current the circuit board can receive is 1.5 A.
I already ...
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Power injecting LEDs with a separate fuse from both sides?
This is in reference to this question. Fusing power injected LEDs from both sides
Reposting for Clarity
I am involved on a project where we will be installing thousands of LEDs (WS2812B Addressable ...
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Fusing power injected LEDs from both sides [closed]
I am involved on a project where we will be installing thousands of LEDs (WS2812B Addressable strips) on the floor. I have a question about about fusing and if there is a more efficient way to go ...
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213
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Why don't Arduinos have a fuse on the Vin pin?
I am designing a PCB for an Arduino Nano. I want to protect the Nano from over current and high voltage. In the schematic of the Nano, there is only one fuse at USB Vcc at Arduino Nano Rev3. No clone ...
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Protection for M-BUS circuit?
From available sources, I've put together a functional M-BUS interface circuit, that allows a 5V MCU to communicate with an M-BUS enabled water meter. It works as intended, so no problem there. The ...
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70
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Second opinion: circuit for camping van
I am customizing a van to take on a camping trip and want to install some electrical applications. With only little experience on this topic I did my research online and drew up a schematic for the ...
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63
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Efuses, inrush and output drooping
Here's a simplified efuse diagram:
Here is the efuse configurations in my circuit:
The load is not present on this pcba. There is a 100mm long cable connecting this board to the load which is a ...
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842
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How can I tell if a slow-blow fuse with a fiberglass center is blown? [closed]
I have a guitar amplifier fuse that I suspect is blown. It looks like a tightly wound spring. I assume the fiberglass center has somehow melted away.
Am I correct in assuming this missing center is ...
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Kenwood Dnx891hd rca output fuse
I have a Kenwood dnx891HD and I've had problems with it for years I finally sent it in due to protect mode and they sent me a picture and told me it was this rca output fuse on the circuit board and I ...
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3
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538
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Using a 0 Ω resistor as a fuse
Can 0 Ω resistors be used as fuses? I can't find any fuses physically small enough to fit on my board that can also take the current we're expecting.
In my application, 58 A is the expected continuous ...
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201
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LiPo Battery (parallel cell) Protection - Fuse Selection to Support BMS
I'm designing a LiPo battery and I'm struggling with the protection, or more specifically, the fuse selection. Can I please have some help? This is a really convoluted problem with a lot of factors, ...
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Powering long LED strip, injecting power. Correct way to fuse?
Recently I asked an opinion based question regarding LED strips. I have learned my lesson and now I have an actual question regarding "how power flows".
I'll explain: I have a lighting ...
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235
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Why are fuses used for appliances that are plugged into the wall socket?
Fuses are there to ensure that the device being used doesn't short circuit and overheat.
How likely is it that the current from a wall socket will actually exceed its given amount of current of, for ...
2
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Identifying and replacing fuse
Circa 1970s Hanimex model 101 record player with built-in pre- and power amplifier PCB stopped outputting audio signal. Found PCB glass-body fuse non-functional. Fuse has 'CONO GDL' and '0.5A250V' ...
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104
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Identifying a resettable fuse marked N⩙
I'm troubleshooting a control board that has a very long replacement lead time (about half a year) and I think I've identified the faulty component. It is – I believe – a surface mount resettable fuse....
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65
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Fuse/PTC voltage derating
For safe operation of a PCB design, do I need to derate the voltage of a Fuse / PTC?
Can I for example assume, that a femtoASMDC008F can be used in a circuit with a nominal voltage of 12V (but ...
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214
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Use of MOVs without fuse?
I understand the MOVs become almost short-circuit when input voltage across them exceed a threshold.
But how does this protect the circuit behind the MOVs? Suppose the input power supply voltage ...
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What is the correct size of fuse for a Igloo Iceless cooler? DC 12v 55w, Stock Fuse 250V 7.5A [closed]
I would like to know if the stock fuse is too big for the cooler, because the original cable to come with the cooler melted at the 12v plug. The plastic around the tip was melted to the point the tip ...
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2
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107
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Turning PNP fully off for fuse indicator
I'm having a little trouble with a PNP based blown fuse circuit. I'm using a similar circuit in other boards for blown fuse indications for 12VDC and 24VDC supplies without issue. I'm trying to ...
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Amp reading on multimeter significantly varies depending on port
I'm using a rapid 318dmm multimeter, and I am measuring the short current of a 5x5 inch solar cell which has a power rating of 2.7 W and a nominal voltage of 0.5 V. I'm measuring the current outside ...
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