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3 votes
Accepted

Why too many MOVs used in surge protectors?

Typical application of MOV looks like this: (image credit and more about the topic here) The image that you have shared seems like eight copies of this circuit, supposed to be wired with eight ...
Whiskeyjack's user avatar
  • 8,361
0 votes

Protective-Earthing the chassis with the earthing point being the star-point - How does it keep the Chassis at Earth potential?

Earthing can't solve all problems. The general mass of the Earth can be assumed to be close to 0V. But if one of the phase wires, say L1, touches the ground near you, it will locally raise the ...
Simon B's user avatar
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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

How to protect a motherboard from an old power supply?

Use one of the TVS Diodes across each rail. Once it turns on, it will clamp the voltage or die trying. Select one large enough, like 5KVA, to blow up any PSU. It costs a buck or two on Mouser.
Dereck's user avatar
  • 652
1 vote

How to protect a motherboard from an old power supply?

A fuse at the output of a power supply, protects it from damage that could be caused by over-current or short-circuit. It definitely cannot protect the load (motherboard in this case). 'Crowbar ...
vu2nan's user avatar
  • 18.9k
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
  • 18.9k
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
1 vote

Type of diodes for 9V

General purpose or Schottky (bit more expensive, but generally less voltage drop = more efficient) with a reverse voltage rating of at least 15V, 25 or 50V preferred and a forward current rating of at ...
vir's user avatar
  • 20.3k
3 votes
Accepted

Jump on varistor I/V curve when "passing" through max. leakage current region to max. clamping voltage region?

The "jump" is in the specifications, it is not real. They guarantee maximum leakage current and (effectively) the minimum clamping current for a given voltage. The centre solid black line is ...
Spehro Pefhany's user avatar

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