What Is an LED？
An LED is a tiny lamp that glows when connected to a current. It has a negative lead and a positive lead and only works when it is connected to the batteries in that way. The negative lead is shorter and is connected to the larger piece inside the glass or plastic dome. The leads are called terminals.
What Is a Diode?
Diode is a term for a family of electronic components that let electricity pass only one way. The LED (light-emitting diode) is one that uses a material that gives off a high degree of visible radiation (light) when a current is passed through it. If the LED does not light, disconnect it immediately and turn the leads the other way in the circuit.
What Are the Leads For?
The leads of the diode, which look like tiny legs, are the positive and negative terminals used to connect it to a circuit. The leads are made of a conducting material and are used to carry the current to the diode. They also help carry heat away from the dome part of the LED.
How Is an LED Different from a Common Light Bulb?
Besides the obvious differences in size and shape, an LED and the common light bulb work differently. An incandescent bulb glows when current is applied because of a high amount of electrical resistance in the titanium bridge (wire) within the bulb. Energy is given off as heat and visiable light. An LED only passes electricity one way and glows when the electrons make the semiconductor crystals get excited and give off a high degree of visible light called photons.
Are All LEDs the Same?
LEDs come in many shapes and sizes, but they all work in basically the same way. They all have a dome to cover the light and two leads to connect to current. Collect the following types of LEDs if you want to ass variety to your circuits.
I. Rectangular II. Miniature III. Jumb
How Is an LED Used in Electronic Devices?
Because the light from an LED is so visible, LEDs are most often used as indicator lights. That is, when an LED is working in a circuit, that is proof the electrons are flowing through that part of the circuit. Think about the indicator lights on VCRs, computers and radios. These lights indicate when there is power to the decives.
What Are the Power Requirements of the LED?
Any of the above LEDs will work in the simple series circuit. Use two flashlight batteries to supply 3 volts. Do not use more than two batteries with only one LED. The LED may overheat and break.
