Physics 7.3.6 Flashcards
The Output Voltage / PD of a Transformer Depends on: (2)
-The Number of Turns on the Primary & Secondary Coils.
-The Input Voltage / PD.
What Equation can be Used to Calculate the Output PD / Voltage of a Transformer?
PD Across Primary Coil / PD Across Secondary Coil = No. of Turns on Primary Coil / No. of Turns on Secondary Coil
What does the Equation ‘Vs / Vp = Ns / Np’ Show?
The Ratio of the Potential Difference Across the Primary & Secondary Coils of a Transformer is Equal to the Ratio of the Number of Turns on Each Coil.
What does a ‘Step-Up Transformer’ do?
A Step-Up Transformer Increases the Voltage/PD of a Power Source.
What does a ‘Step-Down Transformer’ ?
A Step-Down Transformer Decreases the Voltage/PD of a Power Source.
Which Coil on a Step-Up Transformer has More Coils?
A Step-Up Transformer has More Turns on the Secondary Coil than on the Primary Coil. Ns > Np.
Which Coil on a Step-Down Transformer has More Coils?
A Step-Down Transformer has More Coils on the Primary Coil than on the Secondary Coil. Np > Ns.
An Ideal Transformer would be…
100% Efficient.
Why can’t Transformers be 100% Efficient?
Because Although Transformers can Increase the Voltage of a Power Source, Due to the ‘Law of Conservation of Energy’, they Cannot Increase the Power Output.
Step-Up Transformers can Increases the Voltage, but not the Power.
Because Power is Set in Stone, so Increasing the Voltage would really just “Spread Out” the Current over the Circuit. So Current in any given point iof the Circuit Decreases. So like the exam question w/ efficiency & transformers.
Power = Current * PD
If we put this in terms of the equation, Power cannot change here, but PD Increases, so Current must decrease so then Power Value can remain constant. So, it does this by spreading out over the circuit.
P=VI
So becuase P cant change, when V Increases, I must Decrease (to compensate.)
If a Transformer is 100% Efficient:
Input Power = Output Power.
