Electronically controlled lamps: diode and triode

Let's talk about electronically-controlled lamps.

What is an electronically controlled lamp?

Electronically controlled lamps are electrical appliances with a certain number of electrodes, which let the electric current flow in only one direction. The name of the lamp depends on the number of electrodes: a diode (two electrodes), a triode (three electrodes), a pentode (five electrodes), etc. They are used in radio engineering, electronics, power engineering and many other industries, usually to correct an alternating electric current , And also affect the frequency of the current, act as a detector and switch electrical circles. You do not know what the diode and triode are for? Let us begin to correct this gap.

Diode

The diode is an electronically controlled lamp, in which there are two electrodes. The diode and the triode for the hardware component differ precisely in the number of electrodes, remember this. Based on the physical principles of the implementation of the functional, they are divided into such species (respectively, each species is divided into a number of subspecies):

1. Electrovacuum. Used to rectify the current. When the cathode is heated to the required temperature (when thermoelectric emission occurs), an positive voltage is applied to the anode. Then a part of the liberated electrons is directed to the anode and a diode current is formed. If this does not happen, then the electrons return to the cathode.

2. Gas-discharge. Used for amplifiers of considerable power and stabilization of high voltages. They are a cathode and an anode, which are placed in an inert gas medium or a mixture of gases under a certain pressure.

3. Semiconductor. The application possibilities are very diverse. They are devices in which the electrical transition is rectified and there are two external terminals. As an electrical rectifier, an electron-hole transition, a metal-semiconductor contact or a hyper transition is used.

Triode

Unlike a diode, the triode, in addition to the anode and cathode, also has a control electrode, which is called a grid. The grid between the anode and the cathode makes it possible to control the electron beam in the lamp, changing the size and polarity of the voltage between the grid and the cathode. It is because of this ability that the grid is called the manager.

The grid, in most cases, is a spiral of fine wire that surrounds the cathode. They make it from nickel, molybdenum, their alloys, as well as from tantalum and tungsten. The lower the potential in the grid, the more work an electron has to do to go through the field. At certain values of the negative voltage, no electron can stop the grid field, and the anode current of the triode will be zero. Triodes are often used to amplify the signal when receiving radio beams.

Practical use

The triode and diode, the physics of their use, made it possible to step up the development of everything related to electricity in a qualitative way. It is difficult to imagine without them radios, televisions, computers, telephones and many other things. The diode and triode are used not only in large-scale production, but also by radio amateurs and radioelectronics in their home experiments. It is difficult to imagine an advanced PCB that will handle complex technology, and in which there will be no electronically controlled lamps. Diode and triode have a very wide range of uses, so the presence of several unused devices from any radio amateur is almost guaranteed. But with their practical use, you should be careful - they are devices that work with voltage, even small ones, but if you ignore safety techniques, the consequences will be at least unpleasant.