Resistance and Resistors

How does the AWG system affect resistance when gauge size decreases?

Resistance decreases because the conductor is thicker

Why are bus bars used instead of standard circular conductors in large aircraft?

Bus bars can carry large amounts of current with lower resistance

Why are wire-wound resistors suited for high-current circuits?

They can dissipate more heat

If the resistance in a circuit remains constant, what happens to current when voltage is tripled?

The current triples

A circuit requires resistance to limit current but also act as a heating device. Which resistor type would be most appropriate?

Wire-wound resistor

If a conductor's cross-sectional area is doubled, how is resistance affected?

Halved

A 20Ω resistor dissipates 60 V. Which formula correctly calculates the current?

I = E / R

Why is resistance measurement expressed in ohms?

Because it represents voltage per unit current

What does the fourth color band on a resistor indicate?

Tolerance

A resistor with bands red, violet, orange, and gold has what resistance?

27,000 Ω ±5%

What principle allows photoconductive cells to function in cockpit lighting?

Resistance decreases as light intensity increases

A conductor with 40Ω resistance has 80 V applied. What is the current?

2 A

A thermistor in an engine temperature sensing circuit has which characteristic?

Resistance decreases as temperature increases

Why is copper preferred over aluminum in many aircraft electrical systems?

Copper has a lower resistivity than aluminum

Why is the temperature coefficient of copper significant in aircraft applications?

Resistance increases predictably with temperature

Which material decreases resistance when its temperature increases?

Carbon

What distinguishes a rheostat from a potentiometer?

A rheostat has two terminals, while a potentiometer has three

Which factor would most effectively decrease the resistance of a wire without changing its material?

Increasing its cross-sectional area

If a copper wire has a resistivity of 0.017 Ω ·m and its length is doubled, what happens to resistance?

Doubled

Which best explains why fixed resistors are widely used in circuits?

They provide a constant resistance value

Why does doubling the length of a conductor double its resistance?

Electrons encounter twice as many collisions

In a potentiometer used for volume control, which component provides the variable resistance?

Wiper arm

Why is manganin used in precision resistors?

Its resistance is stable with temperature change

Why is a potentiometer usually set to a value higher than the load resistance?

To ensure voltage division and reduce wasted current

How does tolerance affect the reliability of resistor-based circuits?

Narrow tolerance reduces variation from the expected value