This calculator gives the turns ratio of an RF transformer. Enter the input and output impedance.

**Formula**

**Np/Ns = √(Zp/Zs)**

where

- Np = Number of turns in the primary coil
- Ns = Number of turns in the secondary coil
- Zp = Input or Primary impedance
- Zs = Output or Secondary impedance

**Background**

An RF transformer is a passive device that “transforms” or converts an impedance, voltage or current to another desired value.

In addition, a transformer can also be used to isolate DC, reject common

mode signals, and convert balanced impedance to unbalanced or vice versa.

The picture below shows a transformer by Mini-circuits.

RF transformers are specified to operate over a frequency range. The turns ratio is a key parameter and refers to the ratio of the secondary to primary impedance** Zs/Zp.**

Just like any other RF component, transformers have insertion loss, return loss that vary with frequency and a maximum input power level.