Crash Course Electronics/LED - Revision history

Mschied: /* Knowing The LED's color */

2012-06-17T16:24:33Z

Knowing The LED's color

← Older revision		Revision as of 16:24, 17 June 2012
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	=== Knowing The LED's color ===		=== Knowing The LED's color ===
	If the wave length is known the minimum voltage to create light can be calculated [http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon here] or in this [http://www.oksolar.com/led/led_color_chart.htm LED color chart])		If the wave length is known the minimum voltage to create light can be calculated [http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon here] or in this [http://www.oksolar.com/led/led_color_chart.htm LED color chart]) - this method is not very reliable due to several reasons. Better measure it using one of the below methods.

	=== Testing with a Resistor ===		=== Testing with a Resistor ===

Mschied at 12:43, 27 January 2012

2012-01-27T12:43:19Z

← Older revision		Revision as of 12:43, 27 January 2012
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	== Unknown voltage of an LED ==		== Unknown voltage of an LED ==

	There are different methods of determining the voltage of an LED. ~~If the wave length is known the minimum voltage to create light can be calculated<br>~~		There are different methods of determining the (forward) voltage of an LED.
	~~http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon (or [http://www.oksolar.com/led/led_color_chart.htm LED color chart])~~

	If the wave length is ~~unknown~~ the ~~LED can be connected~~ to ~~an adjustable voltage source via a large resistor and the voltage~~ can be ~~gradually increased until a small current flows through the LED (for example 1mA will be ok for most LEDs without destroying them)~~. ~~Then the voltage~~ of ~~the LED can be measured (~~in ~~parallel to the~~ LED).		=== Knowing The LED's color ===
			If the wave length is known the minimum voltage to create light can be calculated [http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon here] or in this [http://www.oksolar.com/led/led_color_chart.htm LED color chart])

			=== Testing with a Resistor ===
			If the wave length is unknown the LED can be connected to an adjustable voltage source via a large resistor and the voltage can be gradually increased until a small current flows through the LED (for example 1mA will be ok for all standard LEDs without destroying them). While running this, the voltage across the LED's legs can be measured. The voltage then can be used for calculations.

			If you have no variable voltage source: Use any voltage source between 5V and 10V and a 5000 ohm resistor - so the maximum current is less than 2mA in any case. Then measure the voltage across the LED.

			=== Testing with Multimeter ===

			The diode tester of a Multimeter internally works similar to the above described method. The Multimeter uses a small voltage and a limited current (usually between 0.1 and 1mA). It displays the voltage across the diode. Some multimeters deliver sufficient current to light the LED very dim (use a dark environment).

			However this doesn't work for all diode testers I have used before - they may only be able to detect voltages up to 1.5V for example - a blue LED (3V) can't be tested this way. Best try with a white LED if it works with your multimeter. If this works it will be fine with all standard LEDs as well.

	== Links ==		== Links ==

Mschied at 12:17, 27 January 2012

2012-01-27T12:17:44Z

← Older revision		Revision as of 12:17, 27 January 2012
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	If the wave length is unknown the LED can be connected to an adjustable voltage source via a large resistor and the voltage can be gradually increased until a small current flows through the LED (for example 1mA will be ok for most LEDs without destroying them). Then the voltage of the LED can be measured (in parallel to the LED).		If the wave length is unknown the LED can be connected to an adjustable voltage source via a large resistor and the voltage can be gradually increased until a small current flows through the LED (for example 1mA will be ok for most LEDs without destroying them). Then the voltage of the LED can be measured (in parallel to the LED).


			== Links ==

			* LED Resistor calculator [http://www.elektronik-kompendium.de/sites/bau/1109111.htm here] or [http://www.led-store.ch/vorwiderstand-rechner.php there]
			* [http://led.linear1.org/led.wiz LED Array Wizard]

	[[Category:Electronics]]		[[Category:Electronics]]
	[[Category:Martin Schied]]		[[Category:Martin Schied]]

Mschied at 12:15, 27 January 2012

2012-01-27T12:15:07Z

← Older revision		Revision as of 12:15, 27 January 2012
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	== Identifying + and - ==		== Identifying + and - ==

	Round LEDs with legs have a short and a long leg when new. The longer leg is the positive leg (anode), the short leg is the negative (cathode). Other LEDs usually have marks which can be found in their data sheets. If the legs of an LED are already cut there's still a flattened part on the LED's marking the negative side.		Round LEDs with legs have a short and a long leg when new. The longer leg is the positive leg (anode), the short leg is the negative (cathode). Other LEDs usually have marks which can be found in their data sheets. If the legs of an LED are already cut often there's still a flattened part on the LED's marking the negative side.

	=== what happens if the polarity is reversed? ===		=== what happens if the polarity is reversed? ===

WSebastian at 17:02, 26 January 2012

2012-01-26T17:02:12Z

← Older revision		Revision as of 17:02, 26 January 2012
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	There are different methods of determining the voltage of an LED. If the wave length is known the minimum voltage to create light can be calculated<br>		There are different methods of determining the voltage of an LED. If the wave length is known the minimum voltage to create light can be calculated<br>
	http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon (~~oder~~ [http://www.oksolar.com/led/led_color_chart.htm LED color chart])		http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon (or [http://www.oksolar.com/led/led_color_chart.htm LED color chart])

	If the wave length is unknown the LED can be connected to an adjustable voltage source via a large resistor and the voltage can be gradually increased until a small current flows through the LED (for example 1mA will be ok for most LEDs without destroying them). Then the voltage of the LED can be measured (in parallel to the LED).		If the wave length is unknown the LED can be connected to an adjustable voltage source via a large resistor and the voltage can be gradually increased until a small current flows through the LED (for example 1mA will be ok for most LEDs without destroying them). Then the voltage of the LED can be measured (in parallel to the LED).

WSebastian: /* Unknown voltage of an LED */

2012-01-26T17:01:09Z

Unknown voltage of an LED

← Older revision		Revision as of 17:01, 26 January 2012
Line 28:		Line 28:

	There are different methods of determining the voltage of an LED. If the wave length is known the minimum voltage to create light can be calculated<br>		There are different methods of determining the voltage of an LED. If the wave length is known the minimum voltage to create light can be calculated<br>
	http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon		http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon (oder [http://www.oksolar.com/led/led_color_chart.htm LED color chart])

	If the wave length is unknown the LED can be connected to an adjustable voltage source via a large resistor and the voltage can be gradually increased until a small current flows through the LED (for example 1mA will be ok for most LEDs without destroying them). Then the voltage of the LED can be measured (in parallel to the LED).		If the wave length is unknown the LED can be connected to an adjustable voltage source via a large resistor and the voltage can be gradually increased until a small current flows through the LED (for example 1mA will be ok for most LEDs without destroying them). Then the voltage of the LED can be measured (in parallel to the LED).

Mschied at 00:50, 26 November 2011

2011-11-26T00:50:53Z

← Older revision		Revision as of 00:50, 26 November 2011
Line 3:		Line 3:
	== Identifying + and - ==		== Identifying + and - ==

	Round LEDs with legs have a short and a long leg when new. The longer leg is the positive leg. Other LEDs usually have marks which can be found in their data sheets. If the legs of an LED are already cut there's ~~usually~~ a flattened part on the LED's ~~ring~~.		Round LEDs with legs have a short and a long leg when new. The longer leg is the positive leg (anode), the short leg is the negative (cathode). Other LEDs usually have marks which can be found in their data sheets. If the legs of an LED are already cut there's still a flattened part on the LED's marking the negative side.

	=== what happens if the polarity is reversed? ===		=== what happens if the polarity is reversed? ===

Mschied at 00:47, 26 November 2011

2011-11-26T00:47:07Z

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-Calculate The voltage of an LED with a distinct wavelenth:<br>
+Light emitting diodes work like normal diodes and so are only conducting in one direction. Current only flows from the positive terminal to the negative terminal.
 http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon
 [[Category:Electronics]]
 [[Category:Martin Schied]]

Mschied: Created page with "Calculate The voltage of an LED with a distinct wavelenth:
http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon Category:Electronics [[Category:Mar..."

2011-11-08T15:53:39Z

Created page with "Calculate The voltage of an LED with a distinct wavelenth:<br> http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon Category:Electronics [[Category:Mar..."

New page

Calculate The voltage of an LED with a distinct wavelenth:<br>
http://www.pveducation.org/pvcdrom/properties-of-sunlight/energy-of-photon

[[Category:Electronics]]
[[Category:Martin Schied]]