Make the First LED From 1907 - H.J. Round

Hello!

LEDs (light emitting diodes) have become indispensable today. Their efficiency is considerably higher than, for example,light bulbs. The electrical energy is therefore converted into light energy much more efficiently. Single LEDs only require currents in the range of 10-20 mA with voltages around 2 to 4 volts.

I can still remember the research into blue LEDs at my university in the mid-1990s. This search even later won the Nobel Prize in Physics. Then around the year 2000 I bought my first blue LED for a project. It cost around 5 euros and I treated it with the greatest caution. But the first LED that my instructables are about is much older.

Henry Joseph Round (1881 - 1966) was an English researcher and is considered the inventor of the light-emitting diode. In 1907 Round discovered that inorganic substances can be made to glow by applying an electrical voltage. This round effect is the basis of today's LED.

To recreate this attempt, you only need the following parts:

• Carborundum or silicon carbide: You can get it cheaply on ebay f.e. carborundum
• a 0-30V low power power supply
• possibly a 200 Ohm / 0.25 W resistor
• a needle or you take one wire-end of the resistor

The circuit diagram is more than simple. The silicon carbide (carborundum) is connected to the positive pole of the power supply unit using an alligator clip. The negative pole goes through a 200 ohm resistor (this does not necessarily have to be used) to a needle. The feed wire of the resistor can be used for this purpose.

The experiment is very simple and can be carried out by the students in a physics class, for example, without any problems.
If you now touch a suitable point on the carborundum with the needle, you can see a faint glow. The luminous phenomena have different colors from orange to green.

If you like my physics-projects take a look at my homepage or my youtube-channel.

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In this sense, have fun experimenting and Eureka