The Metal-Oxide-Semiconductor Field-Effect Transistor, or MOSFET for short, is similar in many ways to the junction FET (JFET). Both are voltage-driven unipolar devices that depend on either electron or hole movement-but not both, as does the bipolar transistor. However, there is a fundamental structural difference between the two field-effect tr
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ansistors: The JFET has three layers while the MOSFET has two. The MOSFET`s simpler construction has give it a performance edge over the JFET, and made it the world`s most popular transistor style. Earlier articles in this series stated that the MOSFET`s controlling gate voltage is applied directly to its channel region across a thin layer of insulating oxide, as shown in Fig. 1-a. This geometry contrasts with that of the JFET, which is controlled by switching an internal PN junction. The MOSFET will work from lower power that the JFET, and its simpler design is reflected in lower production costs. That is why it has become the basis for all CMOS digital logic IC families. Part 9 and Part 11 in this series discussed FET`s. The basic principles of JFET`s and MOSFET`s were explained in the first article of (Electronics Now, February 1993) and the words that describe them were defined. The second article (Electronics Now, March 1993) focused on JFET`s, and included practical JFET circuit schematics. This article concentrates on the enhancement-mode MOSFET, and it includes practical MOSFET circuit schematics base upon small-signal MOS transistors available in a low-cost CMOS integrated circuit. You might wish to review the first two articles to refresh your general knowledge of FET`s before reading this article. There are both N- and P-channel MOSFET`s just as there are both N- and P-channel JFET`s. In the cross-section view of...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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