What is the resistance of a 5 amp fuse?
Copper resistance rises by 0.39% per C so at if at 5 amps it is 100C, the resistance has increased from 0.0085 ohms to 0.012 ohms.
What is the maximum current fuse wire can withstand?
A 5 amp fuse wire can withstand a maximum power of 1 W in circuit.
Why should a fuse have high resistance?
A fuse wire should have a high resistance so that according to (1), a lot of heat is generated and it is easier for the fuse wire to reach its melting point. Also, a high resistance decreases the current flowing in the circuit than what would have been in the absence of it.
When is it OK to blow a fuse?
Fuse is OK: If the multimeter reading changes to a low resistance value (similar to the result of touching the 2 leads together). Fuse is Blown: If the meter reading does not change and display still shows the original 100% resistance state. Don’t forget to turn the multimeter OFF when you have finished testing.
What should be the resistance of a good fuse?
What blows the fuse is the heat generated proportional to the SQUARED value of the current passing thru it. That value, multiplied with its resistance, will be the power consumption on it, which, if too much (hot), will blow it, hence saving the electronics (and preventing a potential fire).
How can you tell if a glass fuse has blown?
Whilst it is easy to visually inspect the element in a glass fuse to see if it has blown, the majority of fuses have solid, non-transparent bodies that hide the element from view. To test if the fuse is blown, we require a multimeter.
What’s the best way to test a fuse?
Place the fuse on a non-conducting surface such as wood, laminate or plastic. Touch the metal caps at each end of the fuse with the metal tips of the testing leads. There is no polarity so you can use any lead for either fuse cap.
Fuse is OK: If the multimeter reading changes to a low resistance value (similar to the result of touching the 2 leads together). Fuse is Blown: If the meter reading does not change and display still shows the original 100% resistance state. Don’t forget to turn the multimeter OFF when you have finished testing.
How is the resistance of a fuse measured?
Once configured, a multimeter can measure the resistance of the fuse element. Resistance is measured in Ohms ‘Ω’. The following tutorial uses a digital multimeter, however the same principles apply when using an analogue multimeter (ie. one with a needle display).
What happens when a fuse is blown on a meter?
If the reading is close to the one you got when you touched the positive and negative leads, the fuse is fine. If the fuse is blown, the meter will not read anything at all, or the meter may say “Open Loop” or “OL.” If you want to use the meter as an ammeter, keep reading! Did this summary help you?
How many amperes does a fuse need to have?
Fuses listed in accordance with UL/CSA/ANCE 248 are required to have an interrupting rating of 10,000 amperes at 125V, with some exceptions (See STANDARDS section) which, in many applications, provides a safety factor far in excess of the short circuit currents available.