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I saw my friend in a workshop use fuses to measure current of a generator and he said that a fuse is more accurate than connecting a light bulb because the light bulb works in current range.

My question is : is he right? (that is more accurate to use a fuse instead of a light bulb to measure generator current? ) does fuse consider a load? Is it a proper way to measure the current of generator?

is Kill-A-watt meter ( like this device: https://www.amazon.com/gp/product/B00009MDBU/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1 ) accurate way to measure current of generator ?

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    \$\begingroup\$ Both are terrible ways to measure current. I would not call it measurement at all. The proper way is with a proper measurement device. \$\endgroup\$ – PlasmaHH Mar 23 '18 at 16:22
  • \$\begingroup\$ what is the best way to measure current ? \$\endgroup\$ – ryan Mar 23 '18 at 16:23
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    \$\begingroup\$ With an ammeter or calibrated shunt and ammeter. \$\endgroup\$ – Solar Mike Mar 23 '18 at 16:26
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    \$\begingroup\$ A fuse if warm rises in resistance but for light loads is a quick and dirty measurement . A shunt that is fixed R is more accurate. A bulb is almost constant current as it heats up since R rises 1:10x \$\endgroup\$ – Sunnyskyguy EE75 Mar 23 '18 at 16:27
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    \$\begingroup\$ Your friend has no clue. A fuse is a protection device, not something to measure a current. \$\endgroup\$ – Bimpelrekkie Mar 23 '18 at 16:42
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Both methods are not recommended and will not be an accurate measurement. In order to measure current you should use an ammeter in electric circuits. Fuse and light load will not be considered as a good method.

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I wouldn't call either the bulb nor a fuse a measurement method.

The bulb may give a subjective idea of how much current based on how bright. The fuse will blow, indicating whether the current has reached the fuse's blow conditions (like how fast it'll blow, tolerance or it could just end up being a bad fuse and blow early).

The indicated meter looks like it will measure your current, among other things. My suggestion is that when deciding on a measuring tool, you consider the expected usage and then compare that to the specifications of the tool.

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A fuse isn't a good way to measure current. There two quality of fuses available, the good quality one like Bussmann blow up quick & the cheapies melt and blow with a delay(kinda bad in some sensitive circuits). The major issue is that fuses don't blow exactly at their ratings. A fuse rated for 5A usually never blows at 5A in most cases. It usually takes 1-2A more to blow the fuse.

The best method would be to use a clamp ammeter or using a series ammeter of the desired range depending on the capacity of the source.

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