Measurement of ultra-low frequencies voltage based on dual-heater thermal converter at the range from 0.01HZ to 1HZ

The paper describes a method for measurement of ultra-low frequencies voltage at the range from 0.01Hz to 1Hz. The method based on the square law of the Dual-heater thermal converter using sinθ2 + cosθ2 = 1 equation to evaluate main impact factors causing the measurement errors. The principle and the preliminary results are presented