with pending fcc regulations to limit radio frequency interference from domestic appliances the exact sizes and types of inductors and capacitors used in the filter circuit will depend upon the specifications called for in such final fcc regulations although this filter circuit is not in the prototype unit it was allowed for in the design of the charger so that it can be incorporated into the charger at such time as fcc regulations are passed power then passes to either two or three teccor q6 ue2d3 4 ue2d3 p power triacs 5 which are controlled by the power up sequence logic 6 there are two fuses and two power triacs in the single phase version of the charger and three fuses and three power triacs in the three phase version the power up sequence logic provides one second of dead time after application of power to the circuit to prevent any spark from occurring while connecting the cord to the vehicle after the one second of dead time a trickle charge period of ten to twelve seconds occurs in order to trickle charge the bulk capacitors preventing a large power surge that would blow the input fuses and damage the charger the power up sequence logic 6 is composed of an lm556 dual timer and a 74c107 dual.