LED direction indicator

An LED indicator with a difference: three alternately lighting LEDs indi- cate a direction, for instance, in a model railway, or to an emergency exit, or to a door on badly lit stair- ways, and so on. When the supply voltage is switched on, the inputs of gates N4... N6 are logic 1, their outputs logic 0, and all LEDs light. One of the RC networks (R1+ P,/C1; R2/C2; R3/C3) will reach the trigger threshold first. Let us assume it is R1+ P1/C1. The output of N1then goes low, the output of N4 goes high, and D1goes out. There is then no voltage for R2/C2, the output of N2 remains logic high, and N5 remains logic low: D2 then lights. Subsequently, the output of N3 goes low, the output of N6 becomes 1, and D 3 goes out. The logic 0 of N3 is, after a delay in Ri + P1/C1, again at the input of N1. The output of N1 leo()) Ie•o) fo•c) lo••) (oo(o) ko•) LED direction indicator from an idea by M Miller goes high, that of N4 goes low, and D1lights. This process repeats itself, so that...