how a transister different from a vacuum tube

hai
im very new to electronics plz help me how a transistor different from vacuum tube

in construction and in functional:?::arrow:

Transistor(bjt) is smaller and lightweight; had no heater requirement , had rugged construction and is more efficient.

there's some difference between bjt and vacuum tube. I advise u completely forget about vacuum there is no usage nowadays, save your time for studying about transistors and their operation as amplifiers

In BJT, the input current is the flow of the carriers having the energy higher than the energy barrier caused by the junction and bias, while in vacuum tubes, the input current is the flow of the carriers having the energy higher than the work function of the cathode metal.

Transistor: Solid State, based on semiconductor charge carriers.
Tube: Based on thermionic emission, obsolete almos everywhere.

transistors are bipolar(BJT) involving two types of carrirers

vacuum tubes are not really that obsolete, although there only remains a few of its family. the crt (cathode ray tube) in your tv sets is considered a vacuum tube. some parts on your tv station transmitter also uses vacuum tubes because tubes can handle larger power than transistors (though some clevers ckt designs also enables transistor to deliver high power but using more parts than their vacuum tube counterpart).

Vacuum tubes uses high voltages to work, so they have not operation so efficient as the transistors have. Vacuum tubes are voltage controlled devices, bipolar transistors are current controlled devices. Transistor come in two brands: NPN and PNP, while vacuum tubes have only one direction for the current. Vacuum tubes are more tolerant to voltage spikes, electromagnetic pulses, etc. Transistors are more compact and smaller. For audio aspects, tubes have different distortion (smoother than transistors, that clip the signal).

Tubes are used nowadays in high end audio amplifiers and in power RF transmission, where semiconductors can not be used.

maziaar83 said:

I advise u completely forget about vacuum there is no usage nowadays, save your time for studying about transistors and their operation as amplifiers

Click to expand...

Tsk, tsk, tsk, not so, maziaar83!

Vacuum tubes are in more demand then ever before, mainly used in the music industry. I can build a 10-watt vacuum tube gitar amplifier and sell it for $2000! Yeah, you read that correctly, 2 grant! A 10-watt tube amplifier compares with about 100 watt transistor amplifier (not sure exactly).
The demand for tube amplifiers has quadrupled in the last couple years. The sound is warm yet powerfull. We all know transistor amplifiers as used in our stereo systems, etc. Their power just doesn't measure up to tubes.

Try to built a tube amplifier on your own and see how much fun it is and satisfactory! If you need diagrams, let me know.

Added after 7 minutes:

saubhik said:

hai
im very new to electronics plz help me how a transistor different from vacuum tube

in construction and in functional:?::arrow:

Click to expand...

Hello saubhik:

The only differences is actually their size and performace. Transistors are cheap to manufacture (7cents for a 2N3904) and easy to troubleshoot. Tubes on the other hand are much more powerful but require a 'warm-up' period, create a heat, are fragile, and expensive. A glass 1N4148 diode is very small, yet the equivalent tube format sticks out like a sore thumb.

After two decades of decline in demand for tubes, they are making a come-back. Escpecially in the music industry. Over-adjusting a tube amp is nothing and very forgiving. Doing the same for a transistor amplifier will surely blow the output transistors! I guess you get the idea...

If you have more questions I will be happy to answer them...

u can try the following link for the datasheet of transistor lhttp://ocw.mit.edu/OcwWeb/Electrical-Engineering-and-Computer-Science/6-301Solid-State-CircuitsSpring2003/Tools/index.htm .FROM THIS U WOULD GET THE Construction of transistors

Also some microwave sources are built by vaccum tubes.

they are different in structure and charachteristics transistors usually use semiconduction thecnology

both transistor and vacuum tubes functionality is to amplify the signals but the way their working princple is different. a transitor is complete madeup of semiconductor materails which are small insize compare to vacuum tubes. the current conduction is combination of hole and electron currents while tubes urrent is completely by electrons emitted by cathode.