RF Transformer Calculator

What is an RF transformer?

An RF transformer is an electromagnetic static device that utilizes the electromagnetic induction principle to transfer the energy from one circuit to another. The basic construction of the RF transformer features two windings-primary & secondary. Both the windings are wound around the air-core/high-permeability ferromagnetic core of the transformer. 

When the primary is applied with an AC voltage, it leads to the AC flow through the primary winding that results in the creation of the alternating magnetic field in the core. This alternating magnetic field mutually couples and cuts the secondary winding and induces emf across the secondary winding. The magnitude of this emf is proportional to the rate of change of flux linkage with the secondary winding and the number of secondary turns. The direction of induced emf can be found by Lenz's law. The secondary winding supplies the load current when a load is connected across it.

RF transformers are ideal for use in impedance matching to maximize the power transfer & suppress signal reflection, step-up/step-down voltage/current, isolating DC & AC circuit while maintaining the AC continuity and balanced amplifiers.

What is the turns ratio of the Transformer? 

RF transformer turns ratio is defined as the ratio of the number of secondary turns to the number of primary turns (Ns/Np) or the ratio of the number of primary turns to the number of secondary turns (Np/Ns).

How is the turn ratio calculated?

The turn ratio of the RF transformer is calculated by using the following formula.

Where,

N_p/N_s = Turn ratio

N_p = Number of turns in the primary coil

N_s = Number of turns in Secondary coil

Z_p= Input/Primary impedance

Z_s= Output/Secondary impedance

Example:

Input impedance = 8,

Output impedance = 40

N_p/N_s = 0.4472

N_s/N_p = 2.2361

Hence Secondary turns are 2.2361 times more than the Primary turns.i.e N_s = 2.2361 x N_p