Key relationship
Vs/Vp=Ns/Np; VpIp=VsIs; Is=Vs/Rload.
Physics · Practical apparatus
Transformer turns and RMS meters
Compare voltage ratio with counted turns. A voltage step-up increases secondary voltage but decreases primary-to-secondary current ratio for conserved power. A load is needed to set actual current.
Open the interactive experiment →Transformer turns and RMS meters
திருப்புகள் விகிதம் மின்னழுத்த விகிதத்தை நிர்ணயிக்கும். இலட்சிய மாற்றியில் உள்ளீட்டு மற்றும் வெளியீட்டு சக்தி சமம்.
Key notes, relationships and model limits
Practical tip
Compare voltage ratio with counted turns. A voltage step-up increases secondary voltage but decreases primary-to-secondary current ratio for conserved power. A load is needed to set actual current.
Common trap
A transformer does not create energy when it raises voltage.
Model limits
Ideal transformer, RMS sinusoidal steady state, perfect coupling and zero loss. Core drawing has schematic loops; labelled turn counts set the model.
What you will learn
Read transformer ratios with two RMS meter pairs.
Try the experiment
Try both scenarios, change one control, and predict the result before checking the graph and readouts.
Think of it this way
Change one input while keeping the others fixed, as you would in a controlled experiment.
Worked example
Np200,Ns400,Vp12 V gives Vs24 V;100 Ω load draws0.24 A secondary.
Why this matters
The model connects transformer turns and rms meters with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
An ideal2:1 secondary-to-primary turns ratio gives Vs/Vp?
- 0.5
- 2
- 4
Read the explanation
Voltage ratio equals turns ratio.
Course connection: Virtual apparatus preparation. Check exact board/exam membership in the syllabus sources. Physical practical work remains necessary.