What is a Diode?
What is a diode? Diodes are frequently used in many electronic circuit designs like other passive materials. In fact, their structure is quite simple. They are basically made of a p-type material and an n-type material. However, diodes are not one type. There are more than one type and there are specific properties for each type. Diodes can be used in low current structures in applications such as RF, as well as in high current applications in power electronics. In addition, some types of diodes can emit light when current passes through them. These types of diodes are called LEDs for short.
Who invented the first diode?
The first discovered diode type is known as “thermionic diode“. Thermionic diodes were invented by Sir John Ambrose Fleming. However, the patent rights belong to the Edison & Swan United Electric Light Company, the company he worked for.
William Hammer, one of Thomas Edison’s assistants, observed a glow in the positive pole of an electric light bulb and a darkening in the negative pole. Later, British scientist John Ambrose Fleming discovered that the same effect could be used as a detector to indicate the presence of radio signals in the environment. He thus patented the first vacuum tube diode in 1904.
When was the semiconductor diode invented?
Ferdinard Braun discovered in 1874 that he could conduct electric current unidirectionally using galena crystals. However, this discovery could not be used in industrial electronics applications in the early days. Its use in industrial applications took place in the 1900s.
As mentioned above, the effects of the diode were discovered at different times. However, it took some time for this information to be used.
What is the symbol for diode in schematic?
The diode symbol in a circuit diagram consists of a triangle drawn perpendicularly on a straight line.
Characteristic of Diode
The best way to understand how diodes work is to study their properties in different circuit structures. Below is a simple circuit structure containing diodes.
Diode Characteristic
The best way to understand how diodes work is to study their properties in different circuit structures. Below is a simple circuit structure containing diodes.
The circuit consists of a voltage source (a simple battery, solar cell, etc.), a diode and a resistor. In this circuit, the polarity of the voltage source is the same as the polarity of the diode. Therefore, electric current flows through the diode.
In the second circuit shown above, unlike the first circuit, the polarity of the diode and the voltage source are opposite. Therefore, no electric current passes through the diode.
In both examples shown above, the voltage applied to the diode is DC voltage. AC voltages can also be applied to the diode. In this case, when the polarity of the diode and the AC voltage source is the same, current will pass, but when it is reversed, current will not pass. In other words, while current passes in half period, current will not pass in half period.