Further Electrical Concepts

Question 1

Magnetic field.

Answer 1

Exist around all magnets and a conductor carrying current.
Always have 2 poles.
Magnetic lines of force will never cross.

Question 2

Induction and Lorentz force.

Answer 2

A charged particle moving through a magnetic field experiences a force at right angles to the direction the particle is moving and the direction applied field. - Lorentz force.

Question 3

Capacitance

Answer 3

Ability to store charge or energy.
C=q/v.
Used to prevent arcing over electrical contacts.

Question 4

Resistor

Answer 4

Controls current or voltage.
Can be fixed or variable.
Directly affects voltage.

Connecting leads, insulating material, spiral groove, resistive film.

Question 5

Heating resistors and thermistors.

Answer 5

Increasing temperature, increases resistance.
Thermistors - resistors that are specifically designed to respond to changes in rpm.

Positive temperature coefficient (PTC) - resistance increases with increasing
temperature.
Negative temperature coefficient (NTC) - resistance decreases with increasing temperature.

Used for current limiting and temperature sensing

Question 6

Circuit rules.

Answer 6

A shorter current has decreased resistance, voltage and so has a higher current. Therefore an increased temperature.