amr mohamed
Occupation: : 369 Date of Birth : 1994-09-29 Join Date : 2010-11-12 Age : 30
| Subject: Using a transistor as a switch Wed 16 Mar 2011, 9:28 pm | |
| Using a transistor as a switchThere are three areas of operation of the transistor is an area of segments Cut OFF in which a Transistor is turned off completely Work and the complex stream = Cefromntqp operating active region And the transistor works Like a microphone, where the compound stream Is the enlarged image of the stream Alhadpomntqp saturation Saturation In which a transistor Working to full capacity any Fully ON and the current complex is the largest Can not be here (ie, stream Complex) based on stream Al Qaeda. Use Transistors as the key electrical When the transistor is used As the key electrical, it works either In the blocks or at the Saturation, in short, be either Ergonomics, such as matte or key. When the transistor Ergonomics (saturation region) is the effort VCE almost zero and here we say that Transistor is not saturated any Can pass more of the stream Compound. The device that control the Runs through this Transistor called pregnancy (LOAD)
(See figure below). Very important observation here
Is that the capacity to be dissipated by transistors are very small You know Why? Because the effort VCE is a very small (approximately Zero) and as we know that the ability Dissipated by the transistor = Stream complex IC × voltage VCE.
Mark
When Any transistor in the case of Saturation, the voltage VCE is Almost zero, and the stream More complex as possible.
Example
You are using the transistor 2N3904, in Aldcanivet Special This transistor, we found that Po = 625 mW that any capacity That this transistor can Dissipation (in the form of heat) Equal to 625 mW. Now If we assume that the voltage VCE = 0.4 V at saturation, this Transistor can pass Stream complex = 1.5 amp (Approximately the result of dividing power The voltage VCE, taking into account Units). But the question now is: Can this transistor Pass this much power Note that the Aldata Special Shit It says that the highest Ic can This transistor is a bear 200 mA? Answer Absolutely not. If the stream was passed 1.5 mA in this Sitvhm transistor. | |
|