Question

A resistor of 10 kΩ has a tolerance of 10% and another of 20 kΩ has a tolerance of 20%. The tolerance of the series combination is nearly

• A. 10%
• B. 20%
• C. 15%
• D. 17%

Answer 1

The correct option is D 17%

$r_1=10k\Omega ,\Delta r_1=\frac{10}{100}\times 10=1k\Omega r_2=20k\Omega ,\Delta r_2=\frac{20}{100}\times 20=4k\Omega$
Maximum tolerance =$\Delta r_1+\Delta r_2$
=1+4=5
$r_1+r_2=10+20=30k\Omega$
% age of tolerance =$\frac{5}{30}\times 100$
=16.67 % =17 %