What is the primary function of transformers?
Transformers alter the voltage or the amperage of electrical current
What happens when the iron core bar of an electromagnet is formed into a closed loop?
The magnetic lines of force cannot escape and remain concentrated
According to Lenz’s Law, how does the current flow in the secondary coil compared to the primary coil?
The current will flow in reverse direction to the current in the primary coil
If the secondary coil has more windings than the primary coil, what happens to the voltage?
Voltage will increase proportionately
What is the transformer law used for?
Used to calculate voltage change
What is the formula for the transformer law?
N_s / N_p = V_s / V_p
What do the variables V_s and V_p represent in the transformer law?
V_s = Voltage in secondary winding, V_p = Voltage in primary winding
What does the ratio N_s : N_p represent?
The turns ratio
If the turns ratio is 20:1, by how much will the voltage increase?
The voltage will increase by 20 X
Calculate the resulting voltage in the secondary coil if the secondary coil has 20,000 turns and the primary coil has 500 turns with 120 volts supplied to the primary coil.
4800 volts in the secondary
What does the law of conservation state regarding power in a transformer?
The total power in the transformer must always be equal
What is the power law formula?
P = IV
How are amperage and voltage related in a transformer?
They are inversely proportional to each other
What happens to amperage if the voltage doubles?
The amperage must be cut in half
What is the formula to calculate current change in a transformer?
I_p / N_s = I_s / N_p
What do the variables I_s and I_p represent in the current change formula?
I_s = Current in secondary winding, I_p = Current in primary winding
If the secondary coil has 20,000 turns and the primary coil has 500 turns with 600 mA fed into the primary coil, what is the resulting milliamperage in the secondary coil?
15 milliamperes in secondary
To step up the voltage in a transformer, how is it constructed?
It is constructed with more turns in the secondary coil than in the primary coil
How is a transformer constructed to step up amperage?
It is constructed with less turns in the secondary than in the primary
What type of transformer increases voltage?
A step-up transformer
What type of transformer decreases voltage but increases amperage?
A step-down transformer
What are autotransformers used for?
To change voltage in small increments
How do autotransformers differ from conventional transformers?
Autotransformers work on the principle of self-induction
What are kVp controls at the x-ray machine console used for?
The settings for the autotransformer leading to a step-up transformer
