Questions regarding physical fuses. Fuses are 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 ...

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Resettable fuses in parallel to limit output current

What are your experiences with this? it is reliable do use PTC smd to limit 15A? the datasheet has a hold value and a trip value. How I choose the values?
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1answer
45 views

Multimeter reports voltage but no power?

I have an Insteon FilterLinc, which is an electrical line filter. It doesn't work. When I connect a lamp to the "filtered" outlet, I get no power. So I stuck multimeter probes into the filtered outlet ...
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3answers
72 views

Do fuses affect a PC PSU's amperage output?

I have a PC PSU powering a load that should pull 20 Amps. I put a 10 Amp fuse in series with the load and the PSU. However, the fuse simply will not burn, and the PSU continues to supply the load, ...
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1answer
65 views

What are the correct zener diode and PTC fuse size?

Noob here. I need to add overvoltage protection to a small, portable solar power system I'm putting together. The solar PV array has a loaded voltage in the 23-26v range and an open circuit voltage ...
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0answers
13 views

SKM15C-05 which fuse for input and output?

I'm very new to this, but I've ordered an SKM15C-05 documented here: http://www.meanwell.com/search/SKM15/SKM15-SPEC.PDF My plan is to use it to power a small SOC unit via power over Ethernet (POE). ...
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1answer
54 views

Fuse blown indicator circuits compilation

I have been working in a compilation of circuits to use that basically show to the user that a fuse has blown up, this is particulary useful in the bench, needless to say I haven’t tested all of them ...
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0answers
10 views

Naive Question -> UK Flat, taking cover off a fuse box [migrated]

I have bought an Energy Monitor to track our electricity usage (hard times...). I now need to put the sensor on one of the cables either next to the fusebox or the meter. Unfortunately I cannot ...
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2answers
29 views

Fuse for AWG 8 wiring

Assuming I put a 60amp fuse to an AWG 8 wire, whats the worst case scenario when a short circuit happens? Therory about short circuits says the current goes to "infinity" however, shouldnt the fuse ...
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6answers
1k views

How To Know If a Fuse Will Work Properly?

I want to know what kind of periodic test we use to test if a current-limiting fuse will normaly open and protect an electronic circuit (a battery charger) if a failure occur (short circuit or over ...
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0answers
36 views

Time-graded overcurrent protection setting

Source: "Protection of industrial power systems" by T Davies. I am the typical calculation for fuses section, page 92, from chapter 5. There is a calculation were the max overload current of the ...
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2answers
86 views

Transistor fuse problem

I can't find out how this transistor fuse works. I know that the R1 is there because of voltage drop 0,7 V when the voltage on output is at its highest possible value. But I don't understand why there ...
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2answers
78 views

DC Motor drawing too many Amps

I have a treadmill incline motor that is blowing its circuits fuse every time it starts to run. This is the motor that lifts the treadmill up and down. The motor is labeled: Output: 65W Input 36VDC ...
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2answers
209 views

Did I choose the correct fuse for my USB powered circuit?

I need to drive a circuit (operational current 150mA) with a USB port. I would like to protect the port with a fuse and from this question I concluded, that what I want is a PTC fuse. Is that the ...
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1answer
66 views

avrdude: initialization failed, rc=-1

when trying to program the fuses I get this known error message: $ sudo avrdude -c usbtiny -p m328p -U hfuse:w:0x05:m avrdude: initialization failed, rc=-1 ...
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3answers
112 views

What is the function of fuse here

The datasheet states that TPS2400 protects the load from an over-voltage, by disconnecting the load from the power supply (Q1 goes off), without blowing the fuse. Why is the fuse F2 here, if there ...
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3answers
78 views

Short Circuit Indicator circuit

This circuit was designed to save electronic components in the assembled board from damage. It gives warning beep if there is a short circuit in the assembled board. Thus it helps to switch off the ...
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4answers
150 views

Turning on a led with negative voltage

I have been using this fuse blown indicator circuit for a bit, it basically works perfectly fine with positive voltages no matter if there is or nor a load connected The problem starts when I feed ...
0
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1answer
39 views

Can't read/write to/from the atmega328p

I cant communicate with the Atmega328p. I've flashed fuses low: 0x59, high: 0xD9 and changed wiring. Now I've connected 16Mhz crystal to the XTAL1, XTAL2 pins, and 2x22pF to the crystal. But I can't ...
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2answers
109 views

How can I work out if a cable can take a momentary current spike?

In this video here, almost 1000A is being run through a 10mm steel bar, and after a minute or so, it melts. https://www.youtube.com/watch?v=YzZ3aJqmT-M So in terms of charge, 60,000C applied for 1 ...
3
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3answers
115 views

Is this the proper way to fuse a DC/DC Converter?

I am designing a solar power system for camping. I'll use a couple different DC/DC converters to provide DC voltages for the specific items I want to power. I want to properly fuse the various ...
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1answer
58 views

Can i replace a 0.75A 76V SMD fuse with a 1.25A 250V one? [closed]

It's for an LCD TV inverter. The seller said I could even use a thin wire. I'm not sure about that that's why I still bought it but I want to make sure before putting it in. It seems that it's for ...
0
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1answer
85 views

4 iPad Air charging circuit indicator led not working

I developed this circuit in order for it to be connected to 4 ipads at the same time the current they use to charge when they are on low battery goes around 1.8Amps, That its working as intended, ...
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2answers
73 views

Bitbang ATMega-328PU with CT210x using avrdude

I have made a breadboard-arduino with an ATMega-328PU and the standard components taking help from http://arduino.cc/en/Main/Standalone I interfaced the CT2102 Breakout Board with this assembly: DTR ...
6
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2answers
561 views

Short circuit protection for high current wearable: fuse, polyswitch, TBU, circuit breaker, something else?

I am thinking about design elements for a rather high current, battery powered, wearable application. Maximum current of 40A at 5V, but typically around a third to a half of that. Power would come ...
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0answers
109 views

Can I determine a formula for fuse disconnection times?

This is the first time I have used this stack site so am not 100% sure this question is on topic (based on the tags I couldn't find) but thought someone may still be able to help me. For those not ...
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4answers
281 views

Why does a 10A fuse blow at 10A and 5V or 10A and 500V?

Something that's always puzzled me: Wire and fuses can handle a given max current, pretty much regardless of voltage. A 10A fuse will blow if you exceed 10A, if the voltage is 5V or 500V. Why is ...
1
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1answer
82 views

Battery power in the home: Fire Safety

I would like to use 12v LED tape powered by an 8 x AA battery holder and switched with a motion sensor. This will be connected in my home 24/7, so I would like to know what precautions (if any) I ...
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2answers
215 views

Turn on an LED when power is lost with a relay

A friend of mine has just finished his race car but is having fan issues. What I want to help him do is setup an LED that turns on when the fans have lost power. Often the fuse blows. I would assume ...
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0answers
229 views

Atmega32 can't verify after setting correct fuses for external crystal. HELP

I am having trouble with some Atmega32A's purchased off from eBay. The MCU's does not seem to be fake as they are functioning properly. I am experiencig the following problem: I want to use external ...
2
votes
1answer
139 views

AC Short-circuit Protection

I have a bunch of electro-mechanical relays on a board intended to switch 220VAC for CFLs. The maximum load on the relays will be 100W with inrush currents of upto 2A (lasting for less than a second). ...
0
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3answers
120 views

What are the big plugs for that you find on high demand devices in North America (120V-Areas)?

Talking about AMEA socket system and 120V. High power demand devices like A/Cs do have bigger plugs with some switches on them. What exactly is their purpose? Seems like a fuse but isn't the socket ...
0
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1answer
114 views

Does any thermal fuse with the same cut off temperature work?

Would any thermal fuse cutoff for 216°C work as a replacement for the fuse in the picture below?
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4answers
280 views

Is it reasonable to use a current limiting diode in place of a fuse?

I'm trying to source some fast-blow 5mA or 10mA fuses but Littelfuse has discontinued the only reasonably affordable ones I have found. My circuit when operating properly will not output more than ...
0
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1answer
128 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. ...
0
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3answers
140 views

preventing blown fuses in simple circuit

I am trying to prevent blowing fuses in a simple circuit: that consists of a battery(12V), fuse, and 2 lights(50W). There are no switches; the lights are connected and disconnected from the live ...
0
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1answer
59 views

Downsides of using 5mm fuses in 6.3mm sockets

For my multimeter I need to replace a fuse. It is 6.3mm in diameter, 25mm long, rated 500mA/250V AC and 1500A interrupt rating. I have a couple of such fuses, but they are 5mm in diameter, and ...
1
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1answer
102 views

Use a relay as a resettable fuse?

I was thinking; If a relay is used to power a circuit AND itself, if the circuit is shorted - the relay should lose its own power and turn off - almost like a resettable fuse. To power it up, I would ...
25
votes
3answers
3k views

Why did my fuse not blow?

I purchased a few fuses to get familiar with their workings, and I was surprised to see that the 100mA fast-blowing fuses I bought happily conducted up to 215mA (6V power supply, 10\$\Omega\$ ...
5
votes
3answers
165 views

Given metal dimensions and material, is it possible to determine the maximum current that the structure can handle? [semiconductor processing]

I have a linewidth structure that has very low resistance. I want to know the maximum current that this structure can handle. Since the resistance of the metal is so low, it's hard to measure the ...
1
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3answers
289 views

AVRDUDE with buring settings of AVR Studio

I make my own electronic boards often with an Atmel ATmega328P. I used AVR Studio for programming. Now I tried to make the same settings with avrdude and it looks, that they are not really ...
1
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3answers
175 views

What do the abbreviations “SPF” and “SPH” mean with respect to fuses? (Single line drawing for 480 V system.)

There are two lines connected between the transformer low voltage side and the 480 V bus, one with a fuse labeled "SPF" that connects to a GE power quality meter, another with a fuse labeled "SPH" ...
1
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1answer
99 views

How can I protect against shorts in low voltage AC ~16V

I'm looking for a method of protecting a circuit against shorting. I would rather not use a regular fuse as I expect I will short the circuit (unintentionally) fairly often (probably once or twice ...
0
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1answer
60 views

Rating for this circuit breaker at 120 voltsAC

Here is a circuit breaker rated 2 amps at 32 volts DC and 2 amps at 250 volts AC What is the amperage it will break at when I apply 120 volts AC
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1answer
325 views

What are the dangers of a DIY fuse in a multimeter?

For the past few years I have been running my Fluke 79III without a fuse in it's F44.100A 1kV fuse holder. This has meant that I've been unable to use the 40mA circuit. When I blew the old fuse, I ...
1
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1answer
2k views

Fuse configuration AVR dude for external 12MHZ crystal in Atmega 168

I have 2 microcontrollers (Atmega 168PA-PU). So far I have run the following program in one of them (say mc1). Now when I run the same code in the other one it gives erroneous results. Someone ...
0
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1answer
112 views

Can I use a 600VAC PTC resettable fuse in a 700VDC application?

I've inherited an old design, and a part used has gone out of production. This part is a PTC resettable fuse, used in a bootstrap circuit, so it's one-shot. When the PTC opens, it has ~700VDC across ...
6
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3answers
146 views

How do I size fuses to handle sudden changes in AC line voltage into a capacitive load?

Suppose I have a rectifier on the AC line, followed by some caps and a load. simulate this circuit – Schematic created using CircuitLab If the AC line is suddenly increased, there's a ...
0
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3answers
425 views

Why is this switched power inlet fused on both load and neutral sides?

I've purchased a Schurter 4304.6090 power inlet for a project and am a bit confused by the fuse configuration. The inlet requires two fuses: one on the load side and another on the neutral side of the ...
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1answer
333 views

How to identify value of a surface mounted fuse

I have a PCB from a WIFI router and there is a lot of little surface mount components. I am looking for fuses, some of them might actually be them. My question is how do I identyfy them and find out ...
7
votes
4answers
607 views

Why aren't high-current ammeters protected with a fuse

Why is it that the low-current range on an ammeter (200mA) is fused and not the 20A range? I recently lost a multimeter because I connected the ammeter in parallel with a power source by mistake. ...