// Model an NTC thermistor with the B parameter formula

// Copyright (C)2020-2023, Philip Munts dba Munts Technologies.
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using static System.Math;

namespace IO.Devices.Thermistor
{
    /// <summary>
    /// Encapsulate an NTC thermistor.
    /// </summary>
    public class NTC_B
    {
        private readonly double myB;
        private readonly double myR;

        /// <summary>
        /// Constructor for a single NTC thermistor object instance.
        /// </summary>
        /// <param name="B">Thermistor B parameter.</param>
        /// <param name="R0">Thermistor resistance in ohms at the specified
        /// reference temperature.</param>
        /// <param name="T0">Thermistor reference temperature in
        /// Kelvins.</param>
        public NTC_B(double B, double R0, double T0 = 298.15)
        {
            myB = B;
            myR = R0 * Exp(-B / T0);
        }

        /// <summary>
        /// Kelvin temperature as a function of the thermistor resistance.
        /// </summary>
        /// <param name="R">Thermistor resistance in ohms.</param>
        /// <returns>Temperature in Kelvins.</returns>
        public double Kelvins(double R)
        {
            return myB / Log(R / myR);
        }
    }
}