the breakdown phenomenon so that the output voltage of the rectifier 300 is applied to the base of the bipolar transistor 632 therefore the bipolar transistor 632 is turned on to form a current path together with the voltage generator 610 and the positive voltage is not applied to the gate g of the triac 623 so that the triac 623 is turned off accordingly a voltage of the ac voltage source ac_in being applied to the node a is applied to the node b through the fuse resistor 200 and through the second current path at this time the surge voltage state of the output voltage of the rectifier 300 indicates that a voltage of the ac power source ac_in is in the surge voltage state which causes the fuse resistor 200 to be open circuited due to the open circuit of the fuse resistor 200 components constituting the rectifier 300 and the pulse generator 400 receive less stress from a voltage of the ac power source in the surge voltage state so the components constituting the power supply are not damaged 0075 fig4 illustrates an electrical apparatus 700 according to another embodiment of the present invention the electrical apparatus 700 includes a power supply 710 supplying an ac voltage according to the power supply illustrated in fig3 the electrical apparatus further includes electrical components 720 and 730 in which the power is supplied to from the power supply 710 since the power supply 710 is protected from a surge voltage as described above with reference to fig3 the electrical components 720 and 730 of the electrical apparatus 700 can receive the power stably from the power supply 710 as stated above the present invention does not.