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2 votes

Multimeter fuse

This meter does not appear to have fuses in either the 10A or mA circuits. The resistors (the two in parallel, or R44, for the respective inputs will shift in value or fail if subjected to a very ...
Spehro Pefhany's user avatar
0 votes

Multimeter fuse

I would expect the fuse to be in the line of the 10A socket, but indeed there's none. The socket is directly connected to the shunt resistors R* (bottom center of image), whose other side is connected ...
PMF's user avatar
  • 692
0 votes

Fuse/PTC voltage derating

You should stay within the ratings. That particular fuse is rated at 12 max so it should be okay at 12V or less. However, note that when you say "nominal" voltage that seems to contradict ...
Spehro Pefhany's user avatar
0 votes

Does sealing low voltage high current fuse box from air exchange affect the current where the fuse blows?

Does sealing the fuse box from air exchange markedly change the temperature where the fuse blows, Temperature does indeed affect a fuse's blowing current. The spec sheet of the Mega fuses has this ...
Davide Andrea's user avatar
4 votes
Accepted

Need to replace an SMD fuse marked "o". Image available

Both the Littelfuse 437 series fuses and Multicomp SMD fuses use letter O for a 2.5A fuse. They both are rated for 32V. If you can idetify the package size and find more data sheets that say "O&...
Justme's user avatar
  • 159k
0 votes

Need to replace an SMD fuse marked "o". Image available

I don't think you have enough information to replace it. Fuses have speeds (slow/fast) and current ratings. If you know neither, a replacement is likely to be incorrect. "O" or "0" ...
juhist's user avatar
  • 1,752
1 vote

Does it matter if a fuse is on a positive or negative voltage?

One more try. Fuses will not work, but a TVS Diode will. A PSU will not generate enough fault current to operate a fuse promptly, if ever. The goal is to protect your device from overvoltages or ...
Dereck's user avatar
  • 652
0 votes

Does it matter if a fuse is on a positive or negative voltage?

Can I use a fuse 5V 0.5A for this -5V rail as if it was 5V 0.5A? Yes.
vu2nan's user avatar
  • 18.8k
8 votes

Does it matter if a fuse is on a positive or negative voltage?

The fuse does not care if it has + at one end or - (and the opposite). They do care about AC vs. DC because AC has less tendency to arc, but that is unimportant at 5V and not much more at 12V. You ...
Spehro Pefhany's user avatar
2 votes

Does it matter if a fuse is on a positive or negative voltage?

A glass fuse is a passive device; it is AC/DC and swings both ways. The question is, why would you do this? You are not protecting anything. An over-current protection device (OCPD) like a fuse can ...
Dereck's user avatar
  • 652
1 vote

Does it matter if a fuse is on a positive or negative voltage?

I have a power supply with +5 and -5 volts output. Can I use the same fuse for both of them rated 5v 2a? Is this a bipolar power supply with +5, 0, -5 V outputs? If so, you can use the same type of ...
Graham Nye's user avatar
  • 4,423
6 votes

Does it matter if a fuse is on a positive or negative voltage?

Yes. Fuses are non-polar. The fuse is a thermal device. It contains a material that melts at a relatively low temperature. The heat for the melting process comes from the current (energy) passing ...
DrFriedParts's user avatar
  • 12.7k
1 vote

Does it matter if a fuse is on a positive or negative voltage?

Fuses do not care about conventional agreements of people regarding positive or negative voltage.
Stefan Wyss's user avatar
  • 7,653
0 votes

Rated current vs melting integral of fuses

One is not lower than the other, because both are different units. The melting integral is energy, while the current rating is current. In your example with 0.02A^2s for 1s you only get 0.141A, but ...
Stefan Wyss's user avatar
  • 7,653
3 votes
Accepted

Rated current vs melting integral of fuses

The I^2t rating is a pulse rating and it applies for short pulses, for example < 0.008 seconds for one particular type, and < 1ms for very fast-break fuses. See the manufacturer's data for more ...
Spehro Pefhany's user avatar
0 votes

Why are the 10A inputs on many multimeters unfused?

I'll provide a reason why it may not be such a bad thing after all to have an unfused input. I have blown a multimeter fuse on the 10A input several times. At first, I didn't understand what happened ...
juhist's user avatar
  • 1,752

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