Electronics - Resistance and Power - Discussion
Discussion Forum : Resistance and Power - General Questions (Q.No. 5)
5.
With 1 mA of current, what wattage rating should a 470 ohm resistor have?
Discussion:
16 comments Page 1 of 2.
Engr Faizan Rais said:
7 years ago
p=i^2*R.
So putting the values:
p = (40mA)^2*470
p = 0.751W
So, 0.751 w is nearer value to 1 w, the ans is 1 watt.
So putting the values:
p = (40mA)^2*470
p = 0.751W
So, 0.751 w is nearer value to 1 w, the ans is 1 watt.
(2)
Rajesh said:
6 years ago
0.00047 less than 1/4 watt so least one is 1/4 watt is right answer.
1000mW = 1W, 0.250W is correct.
1000mW = 1W, 0.250W is correct.
(2)
Soni said:
8 years ago
P= IV, P=I*I*R.
1*10^-3*10^-3*470,
=0.00047w.
1*10^-3*10^-3*470,
=0.00047w.
(1)
Manikanta said:
1 decade ago
P=I^2R, So
P = 1*10^-6*470 = 0.00047W. How will come 1/4. Please explain?
P = 1*10^-6*470 = 0.00047W. How will come 1/4. Please explain?
Rathi said:
1 decade ago
@Manikanta.
Yes you are right.
But we should take the wattage of the resistance greater than calculated value.
0.25(i.e 1/4) is greater than 0.00047W, So 1/4 is enough.
That means 1/4 watt is the right answer.
Note: If 1/8watt is given in option then 1/8 will be the correct answer.
Yes you are right.
But we should take the wattage of the resistance greater than calculated value.
0.25(i.e 1/4) is greater than 0.00047W, So 1/4 is enough.
That means 1/4 watt is the right answer.
Note: If 1/8watt is given in option then 1/8 will be the correct answer.
Domy dimal said:
1 decade ago
0.25 w is greater than 0.00047w. Then how?
Theophillus said:
1 decade ago
I don't understand how did you get 0.25 W there seriously.
Vasava said:
10 years ago
I can't understand how it come 0.25 watt?
Priyank sharma said:
9 years ago
Why its answer is 0.25watt?
A.sathish said:
9 years ago
0.00047w is correct, which is the nearest value.
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