Question and Answer

Q1. Consider the two structures shown below. Both these structures have identical perimeter( 24 cm). Which of these two structure will have smaller loop inductance.

A. Structure 1
B. Structure 2
C. Both structures will have equal loop inductance

Q2. Consider the inductance of straight wire. Which of the following has a greater effect on the inductance of wire.

A. Length of the wire.
B. Diameter of the wire.
C. Both of these have same effect.
Q3. A 0603 SMD resistor mounted in normal condition has
A. Mainly Capacitive parasitic
B. Mainly Inductive parasitic


Answer and Explanations

1. A => By keeping the traces close, the magnetic lines of loop cancel and give rise to lower loop inductance. The structure B is the kind of structure you will follow for power and ground routing (keep power and ground traces close).

2. A, The inductance of the wire depends more upon the length of wire. Doubling will not double the inductance; it will only marginally increase it.

3. B In its normal mounting condition, the metallic layer on a resistor resides on the top surface. This being a bit far from the ground layer makes it somewhat inductive.


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