Thread: Hooking LED to DS
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Unread 13-01-2009, 08:21
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Re: Hooking LED to DS
To connect an LED to the Driver Station digital output, connect one end of a 100 - 200 ohm resistor to the upper digital output pin, then connect the other end of this resistor to the anode on an LED, and connect the cathode of the LED top the lower pin (ground) on the driver station.


The sketch below shows a schematic for this.

UPPER PIN ----/\/\/\/\-----|>|---- LOWER PIN
....................150 ohm......LED

A typical red LED has a forward voltage of about 2.2 volts, and gives good brightness with ~ 20 ma of current through it. This means that the resistor needs to drop 5 - 2.2 volts, or 2.8 volts. Using Ohms law (R= E/I) gives a resistor value of 2.8/.02 = 140 ohms. 150 ohms is a standard value, and will work well.
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