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Topic: LED problem (Read 1 time) previous topic - next topic

CrossRoads

Put the 01, 10, 11 as address bits into different logic - like a 74xx138, 74xx139 - selected out (#1, 2, 3) will go low, pull one cathode low.
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pranoy

I want the LED to be ON one at a time with the ouputs ( 01,10,11)


There is only one 220 ohm resistor at one of the output pins.


I don't have enough pins so i have to go with 2 pins itself.

the ???????????????? is something i got from chatting in fb.

Grumpy_Mike

Quote
There is only one 220 ohm resistor at one of the output pins.

You need another on the output of the logic gate.

pranoy

this is a fair ckt dgm with only one yellow LED

pranoy

thanks mike

but i tried it in a 2 way traffic scenario. but still the yellow light turns ON when Red comes in one of the tracks

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