A step-down transformer decreases the voltage and a resister also do the same thing, then what is the difference
Answers
Answer:
Looking closely at the numbers in the SPICE analysis, we should see a correspondence between the transformer’s ratio and the two inductances. Notice how the primary inductor (l1) has 100 times more inductance than the secondary inductor (10000 H versus 100 H), and that the measured voltage step-down ratio was 10 to 1. The winding with more inductance will have a higher voltage and less current than the other. Since the two inductors are wound around the same core material in the transformer (for the most efficient magnetic coupling between the two), the parameters affecting inductance for the two coils are equal except for the number of turns in each coil. If we take another look at our inductance formula, we see that inductance is proportional to the square of the number of coil turns:
Inductance formula
So, it should be apparent that our two inductors in the last SPICE transformer example circuit—with inductance ratios of 100:1—should have coil turn ratios of 10:1, because of 10 squared equals 100. This works out to be the same ratio we found between primary and secondary voltages and currents (10:1), so we can say as a rule that the voltage and current transformation ratio is equal to the ratio of winding turns between primary and secondary.
step down transformer example
Step-down transformer: (many turns :few turns).
The step-up/step-down effect of coil turn ratios in a transformer is analogous to gear tooth ratios in mechanical gear systems, transforming values of speed and torque in much the same way:
Torque reducing gear train steps torque down, while stepping speed up.
Torque reducing gear train steps torque down, while stepping speed up.
Step-up and step-down transformers for power distribution purposes can be gigantic in proportion to the power transformers previously shown, some units standing as tall as a home. The following photograph shows a substation transformer standing about twelve feet tall:
Substation transformer.
Substation transformer.
REVIEW:
Transformers “step up” or “step down” voltage according to the ratios of primary to secondary wire turns.
Transformers “step up” or “step down” voltage according to the ratios of primary to secondary wire turns.
A transformer designed to increase the voltage from primary to secondary is called a step-up transformer. A transformer designed to reduce the voltage from primary to secondary is called a step-down transformer.
The transformation ratio of a transformer will be equal to the square root of its primary to secondary inductance (L) ratio.
voltage transformation ratio formulas.