LEDs

ElectronicsLight Emitting Diodes (LEDs)

Terry Sturtevant

Wilfrid Laurier University

April 17, 2012

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

LEDs (Light Emitting Diodes)

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

anode (+) cathode (-)

The LED lights up when current flows from the anode to thecathode..

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

anode (+) cathode (-)

The LED lights up when current flows from the anode to thecathode..

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

You must use a resistor to limit the current.Without a resistor, the LED will probably be destroyed.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

You must use a resistor to limit the current.

Without a resistor, the LED will probably be destroyed.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

You must use a resistor to limit the current.Without a resistor, the LED will probably be destroyed.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

The resistor can go before or after the LED.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

The resistor can go before or after the LED.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

The resistor can go before or after the LED.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

If the LED is reversed, it won’t light up.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

If the LED is reversed, it won’t light up.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

If the LED is reversed, it won’t light up.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here are some different LEDs.

Note that even though they are different shapes and colours, theyall have one pin longer than the other.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here are some different LEDs.

Note that even though they are different shapes and colours, theyall have one pin longer than the other.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here are some different LEDs.

Note that even though they are different shapes and colours, theyall have one pin longer than the other.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

On a breadboard, an LED can be connected to a resistor like this.

The signal would connect at the top of the LED.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

On a breadboard, an LED can be connected to a resistor like this.

The signal would connect at the top of the LED.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

On a breadboard, an LED can be connected to a resistor like this.

The signal would connect at the top of the LED.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here it is completely connected.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here it is completely connected.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

As stated previously, the resistor can be before the LED as well.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

As stated previously, the resistor can be before the LED as well.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here’s an easy mistake to make.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here’s an easy mistake to make.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here’s an easy mistake to make.

This looks like it should work, but it doesn’t.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here’s an easy mistake to make.

This looks like it should work, but it doesn’t. Note that both pinsof the LED are in the same row, so no current goes throughit.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

It’s easier to see what’s going on from the side.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

It’s easier to see what’s going on from the side.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

It’s easier to see what’s going on from the side.

From this angle you can see that both pins of the LED are in thesame row.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

LEDs can also be used for active low signals.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

LEDs can also be used for active low signals.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

LEDs can also be used for active low signals.

Notice the signal is connected to ground to light the LED.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

The LED and resistor can be reversed, as always.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

The LED and resistor can be reversed, as always.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

The LED and resistor can be reversed, as always.

The signal is again connected to ground to light the LED.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here’s a summary.

The two on the left are connected for active low signals.The two on the right are connected for active high signals.Both possible arrangements of resistor and LED are shown ineach case.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here’s a summary.

The two on the left are connected for active low signals.The two on the right are connected for active high signals.Both possible arrangements of resistor and LED are shown ineach case.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here’s a summary.

The two on the left are connected for active low signals.

The two on the right are connected for active high signals.Both possible arrangements of resistor and LED are shown ineach case.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here’s a summary.

The two on the left are connected for active low signals.The two on the right are connected for active high signals.

Both possible arrangements of resistor and LED are shown ineach case.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)

LEDs

Here’s a summary.

The two on the left are connected for active low signals.The two on the right are connected for active high signals.Both possible arrangements of resistor and LED are shown ineach case.

Terry Sturtevant Electronics Light Emitting Diodes (LEDs)