English Traffic Lights

Traffic Lights Animation Led Arduino

In this project we will make traffic lights animation in England, not know is its setting same with traffic lights in Indoensia. For this project certain we use led with color red, yellow, and green. Now we are going to look for how resistance value will be used for each.

Look for resistance value for red led
According to Red Led 5mm diffused datasheet, its Forward Voltage (V_F) is 2 Volt and maximum is 2,5 Volt. So red led safe to operate at voltage range 2 - 2,5 Volt. According to Red Led 5mm diffused datasheet its Forward Current (I_F) is 20 mA. Output voltage from Arduino is 5 Volt

On series circuit like picture above, V_output = V_Led + V_Resistor.

If we use operating voltage 2 Volt for red led, then voltage for resistor (V_Resistor) is V_output – V_Led = (5 – 2) Volt = 3 Volt, forward current (I_F) on red led is 20 mA, cause its circuit is series, certain current flows on resistor is also 20 mA, so that resistance value is needed is:


If we use operating voltage 2,5 Volt for red led...

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