A phase change material switch device , comprising: a phase change material , a heater device (13; 13A-13C) thermally coupled to the phase change material , wherein the heater device (13; 13A-13C) comprises N heaters, wherein N is greater than 1, a power source (15; 50), a coupling device electrically coupled between the power source (15; 50) and the heater device (13; 13A-13C), a first device terminal coupled to the phase change material , a second device terminal coupled to the phase change material , and an impedance device (80A-80F) coupled between the first device terminal and the heater device (13; 13A-13C), wherein the coupling device is configured to: provide a first electrical impedance between the power source and the heater device (13; 13A-13C) in a first state where current supplied to the heater device (13; 13A-13C) from the power source (15; 50) for heating the phase change material , and provide a second electrical impedance between the power source (15; 50) and the heater device (13; 13A-13C) higher than the first electrical impedance in a second state outside heating phases of the heater device (13; 13A-13C), characterized in that for at least one of the N heaters the impedance device (80A-80F) comprises a first impedance element coupled between the first device terminal and a first terminal of the respective heater, and a second impedance element coupled between the first device terminal and a second terminal of the respective heater. a phase change material , a heater device (13; 13A-13C) thermally coupled to the phase change material , wherein the heater device (13; 13A-13C) comprises N heaters, wherein N is greater than 1, a power source (15; 50), a coupling device electrically coupled between the power source (15; 50) and the heater device (13; 13A-13C), a first device terminal coupled to the phase change material , a second device terminal coupled to the phase change material , and an impedance device (80A-80F) coupled between the first device terminal and the heater device (13; 13A-13C), wherein the coupling device is configured to: provide a first electrical impedance between the power source and the heater device (13; 13A-13C) in a first state where current supplied to the heater device (13; 13A-13C) from the power source (15; 50) for heating the phase change material , and provide a second electrical impedance between the power source (15; 50) and the heater device (13; 13A-13C) higher than the first electrical impedance in a second state outside heating phases of the heater device (13; 13A-13C), provide a first electrical impedance between the power source and the heater device (13; 13A-13C) in a first state where current supplied to the heater device (13; 13A-13C) from the power source (15; 50) for heating the phase change material , and provide a second electrical impedance between the power source (15; 50) and the heater device (13; 13A-13C) higher than the first electrical impedance in a second state outside heating phases of the heater device (13; 13A-13C), characterized in that for at least one of the N heaters the impedance device (80A-80F) comprises a first impedance element coupled between the first device terminal and a first terminal of the respective heater, and a second impedance element coupled between the first device terminal and a second terminal of the respective heater. <EOS>