What is the correct voltage transformation ratio condition for a step up transformer?

Transformation ratio of transformer is given by K = V2/V1 = E2/E1 = N2/N1.

• Where N1 is the number of primary turns
• V1 is the primary voltage
• N2 is the number of secondary turns
• V2 is the secondary voltage
   

Step-up transformer:

• A transformer that increases the voltage from primary to secondary (more secondary winding turns than primary winding turns) is called a step-up transformer.
• Therefore, K > 1
   

Step down transformer:

• A transformer that decreases the voltage from primary to secondary (more primary winding turns than secondary winding turns) is called a step-down transformer.
• Therefore, K < 1