This simple Calculator allows you to design an output transformer for tube amplifier operating in a push-pull configuration. Calculations are based on the relationships described in the article - Designing output transformers - published in Radioamator i Krótkofalowiec 1974/12 magazine. Using the Calculator is easy. Define the input parameters and press the [Calculate] button. The keys labeled Reset are designed to restore the default/example values.

The Calculator also allows you to become familiar with the additional parameters of the transformer, which are calculated as the intermediate values ​​used to determine the basic parameters.

Input parameters (they have to be defined before calculation)
Outpu power [W]
Load impedance [Ohm]
Lower frequency limit [Hz]
Upper frequency limit [Hz]
Working resistance of output stage [Ohm]
Working class -
Calculated output transformer parameters (you can't modify them manually)
Minimum cross-section of the core [cm2]
Number of turns of the primary winding -
Wire diameter of the primary winding [mm]
Number of turns of the secondary winding  
Wire diameter of the secondary winding [mm]
Maximum cross section of the core [cm2]
The amplitude of the EMF [V]
The primary winding inductance [H]
Number of turns from the condition of the induction in the core -
Number of turns from the condition of the inductance -
Turns ratio -
The length of wire in the coil [m]
The average path length of the magnetic flux [cm]
Resistance of the primary winding [Ohm]
Resistance of the secondary winding [Ohm]
Additional parameters (they can be modified before calculation)
Magnetic permeability of the core -
The efficiency of a transformer -
Permissible value of induction in the core [T]
The column width of the central core (a) [mm]
The width of the core window (b) [mm]
The height of the core window (c) [mm]