subject: Transistor:The Most Helpful Device in Electronic [print this page] Transistor:The Most Helpful Device in Electronic
Do you know a device that has biggest responsibilities in electronics field? The answer is transistor. Because of its advantages such as cheap, small, and efficient, this device is used to replace the vacuum tube in most electrical appliances. Products that use transistor are communication satellite, mini radios, high-speed computer, etc will be impossible without this little device.
Transistors, similar to semiconductor diodes, are derived from germanium materials or silicon. As the same as in the semiconductor, the material of germanium or silicon is altered to get N- or P- type of semiconductor materials. Here, the diode works as a switch (closed or open circuit), while the transistor is functioned as a device to control the current. That is why, the current may different from almost none (zero) to some maximum value.
Now, we will look at the action on a diode. P- Substance contains Holes or zero value electrons while N- material contains large amount of electrons. As well as the diode is comprised, the electrons and the holes close to the PN junction interact.
The process on the junction makes the P- material less negative close to the junction and the N- material with less positive close to the junction will set up a Barrier or Potential Hill to stop any further recombination. As well as the diode is Forward Biased (P- material positive and N- material negative), the barrier will overcome it and the diode direct the current.
Nevertheless, as well as the diode is Reverse Biased (P- material negative and N- type material positive), the barrier is improved and only less reverse current flows. A term that is used to describe the holes that flow in the P- and the electrons that flow in the N- during the forward bias conditions is Majority Carriers. On the other hand, the electrons and the holes are named as Minority Carriers.
