Unit 2

Number of turns of wire, flux density, and the speed of the cutting action

3 factors that determine the amount of voltage that will be induced in a conductor are

Conductor, magnetic field, and movement

3 important factors concerning magnetic induction

Diode

A device often used to prevent induced voltage spikes when the current flows through an inductor is stopped is the

Metal Oxide Varistor (MOV)

A device that can be used for spike suppression in either dc or ac circuits

One Henry

Coil has an inductance or this value when a current change of one ampere per second results in an induced voltage of one volt.

exponential curve

Describes the rate of certain occurrences and is divided into 4 time constants and can often be found in nature

63.2%

Each time constant in an exponential curve is equal to

Silicon

Has a forward voltage drop of 0.7 V

T=L/R

How do you find the time necessary for current in an inductor to reach it's full ohms law value?

Connect a resistor to source or direct current

How do you measure rise time of current in a inductor?

100,000,000

How many lines of flux are equal to one weber

short

If a switch on a dc circuit is closed, is the circuit acting as a short or open?

oppose it

Induced voltage polarity always does what to applied voltage?

Eddy current

Iron core inductors cannot he used for high frequency applications because of what loss and hysteresis loss in the core material.

True

Many devices use collapsing magnetic fields to generate extremely high voltage.

Inductance

Measured in Henries and represented by the letter L

Induced voltage

This is proportional to the rate of change of current (speed of cutting action)

R-L Time Constant

Time needed for inductor to reach full Ohms law value

Keep current flowing in the same direction

What does induced voltage attempt to do in a circuit?

voltage increases

What happens to the voltage as resistance increases?

Voltage is induced into the conductor

What happens when a conductor cuts through magnetic flux?

Current rises instantly to the max value

What happens when a resistive load is suddenly connected to a source of direct current

Polarity of induced voltage

What is determined by the polarity of the magnetic field in relation to the direction of movement.

magnetic induction

What is the principle or term called whenever a conductor cuts through magnetic lines of flux, a voltage is induced into the conductor.

Lenz's Law

What law states that Induced voltage or current opposes the motion that causes it

voltage spike

What occurs when the current flow through an inductor stops, and the current decreases at an exponential rate also.