Time would be much better spent on explaining transistor and MOSFET behaviour in a simpler way and getting on with digital circuitry and microcontroller projects. You simply cannot put a transistor into a circuit and expect it to produce the calculated results. The gain of a transistor can be from 100 to 200 in a batch and this changes the outcome by 50%!
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There are thousands of transistors and hundreds of different makes, styles and sizes of this amazing device. But there are only two different types. NPN and PNP. The most common is NPN and we will cover it first. There are many different styles but we will use the smallest and cheapest. It is called a GENERAL PURPOSE TRANSISTOR. The type-numbers on the transistor will change according to the country where it was made or sold but the actual capabilities are the SAME. It is also referred to as a BJT (Bi-polar Junction Transistor) to identify it from all the other types of transistors (such Field Effect, Uni-junction, SCR, ) but we will just call it a TRANSISTOR. Most small transistors have a plastic case and the leads are in a single line. The side of the transistor has a "front" or "face" with markings such as transistor-type. Fig 10 has a capacitor on the input and output. This means the stage is separated from anything before it and anything after it as far as the DC voltages are concerned and the transistor will produce its own operating point via the base resistor and LOAD resistor. We have already explained that the value of the two resistors should be chosen so the voltage on the collector should be half-rail voltage and this is called the "idle" or "standing" or "quiescent" conditions. When the voltage on the collector is mid-rail, the transistor can be turned off a small amount and turned on a small amount and the...
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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