For an ideal step up transformer :
- (a)$$\begin{aligned}\frac{\text {Voltage}_\text{primary}}{\text {Voltage}_\text{secondary}} \gt 1 \\[1 em]\end{aligned}$$
- (b)$$\begin{aligned}\frac{\text {Current}_\text{primary}}{\text {Current}_\text{secondary}} \lt 1 \\[1 em]\end{aligned}$$
- (c)$$\begin{aligned}\frac{\text {number of turns}_\text{primary}}{\text {number of turns}_\text{secondary}} = 1 \\[1 em]\end{aligned}$$
- (d)$\frac{\text {power}_\text{primary}}{\text {power}_\text{secondary}} = 1$
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$\frac{\text {power}_\text{primary}}{\text {power}_\text{secondary}} = 1$
Reason — The step up transformer is used to change a low alternating voltage to a high alternating voltage (of same frequency) i.e.,
VSecondary > VPrimary
⟹ $\frac{\text {Voltage}_\text{secondary}}{\text {Voltage}_\text{primary}} \gt 1$
Also,
In a step up transformer, the number of turns in the secondary coil is more than the number of turns in the primary coil i.e.,
number of turnsSecondary > number of turnsPrimary
⟹ $\frac{\text {number of turns}_\text{secondary}}{\text {number of turns}_\text{primary}} \gt 1$
And
The current in primary coil is more than in the secondary coil i.e.,
Currentprimary > Currentsecondary
⟹ $\frac{\text {Current}_\text{primary}}{\text {Current}_\text{secondary}} \gt 1$
As, for an ideal transformer, when there is no energy loss, the output power will be equal to the input power. i.e.,
powerprimary = powersecondary
⟹ $\frac{\text {power}_\text{primary}}{\text {power}_\text{secondary}} = 1$