Test 10 Flashcards
It takes _______ time constants for a circuit to reach full value
5
On a transformer _________ lags ________ by _________degrees
Current lags voltage by 90 degrees
What is the movable part of a relay
Armature
What is the purpose of an solenoid
Convert an electrical signal to a mechanical motion
More windings on a primary coil is a ________ transformer
Step down
Inductive resistance formula
Xl= 2pi x fL
Inductive resistance = 2 times 3.14 times frequency times inductance
H =
L =
H is Henry
L is inductor
Inductance of a coil is inversely proportional to its _______
Length
In an inductor _________ leads __________
Voltage leads current
Eli the iceman
More current equals ________ magnetic field
Stronger
When electrons flow __________ and ___________ are created
Heat and a magnetic field
4 factors affecting inductance
Permeability of core material
Number of turns of wire
Core length
Cross sectional area of the core
What are the two parts of a relay
Coil and set of switch contacts
What are the two parts of a solenoid
Coil and plunger
Counter EMF can happen when current is ________
Increased
Inductance is measured in
Henries
More windings on secondary coil is a _______ transformer
Step up
EMF is over in _______ time constants
5
What type of transformer has a turns ratio of less than 1
Step down
In a series RL circuit the voltage across a resistor is in ________ with the current
Phase
T = _____/_______
T = L/R
Counter EMF is created when electrons __________ and then it ___________
First begin moving and then it fades away
Changing magnetic field
Induces current
Inductors ___________ a change in current
Oppose
