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  1. tiffanyc

    EPCS4SI8N datesheet

    I don't understand whicht two are you comparing, but I have found a definitely right datasheet of EPCS4SI8N for you at here Hope you it will be helpful to you.
  2. Here you can find the datasheet you want, and I guess that you can consult the online customer service.
  3. PIC18F4550 PIC18F4550 belongs to pic18f family of microcontrollers. PIC18F4550 is one among the advanced Microcontrollers from the microchip technology. This microcontroller is very famous in between hobbyist and learners due it functionalities and features such as ADC and USB Integration. A typical PIC18F4550 comes in various packages like DIP, QPF and QPN. These packages can be selected according to the project requirement. FEATURES PIC18F4550 is an 8 bit microcontroller. PIC18F4550 has been implemented withNano WATT technology hence it requires very low power for its operation. PIC18F4550 has 16 bit Instruction Set Architecture, (ISA) which provides a degree of freedom to programmers with various data types , registers , instructions, memory architecture, addressing modes, interrupt and IO operations. PIC18F4550 also has an Extended Instruction Set as a special feature; it’s an optional extension to the PIC18 instruction set. Memory Specifications: A PIC18F4550 has 256 bytes of EEPROM (Electrically Erasable and Programmable Read Only Memory), 2KB of SRAM (Static RAM) and 32KB of flash memory which in return proves another degree of freedom to programmers. Communication Protocol: PIC18F4550 is remarked as advanced, as it uses well sophisticated protocols for communications. The modern protocols like USB, SPI, EUSART, are well supported in PIC18F4550. These technologies integrate with Nano Watt Technology (as mentioned before) to produce PIC18F4550, a well equipped, low power consuming microcontroller. A Dedicated ICD/ICSP Port allows the programmers to code and debug easily. Enhanced flash program and the 1KB Dual Access RAM for USB are used for buffering. PIC18F4550 consists of up to 13 channels for analog to digital converter. The converter accuracy amounts to 10-bit to convert analog to digital signal relatively. PIC18F4550 is compatible to work with different internal and external clock sources. It comes with four built-in timers or an external oscillator can be interfaced for clocking. The frequency limit for a PIC18F4550 is from 31 KHz to 48 MHz respectively. The microcontroller PIC18F4550 comes with ADC comparators and other such peripherals as an in-built feature. A very good description and in detailed features of PIC18F4550 microcontroller can be found in its respective datasheet. A copy of that PIC18F4550 Datasheet can be downloaded from kynix’s website.
  4. Amplifier Classes Explained Not all amplifiers are the same. Generally, amplifiers are classified according to their circuit configuration and method of operation, and as such Amplifier Classes are used to differentiate between them. Amplifier classes range from entirely linear operation (for use in high-fidelity signal amplification) with low efficiency, to entirely non-linear (where faithful reproduction is not so important) operation with high efficiency, while others are a compromise between the two. Amplifier Classes are mainly lumped into two basic groups. The classically controlled conduction angle amplifier forming amplifier classes A, B, AB and C, which are defined by the length of their conduction state over some portion of the output waveform, such that the output stage transistor operation lies somewhere between being “fully-ON” and “fully-OFF”, and the so-called “switching” amplifier classes of D, E, F, G, S, T etc, that are constantly being switched between “fully-ON” and “fully-OFF”. The most commonly available amplifier classes are those that are used as audio amplifiers , mainly A, B, AB and C and to keep it simple, it is these amplifier classes we will look at here in this amplifier classes tutorial. Class A Amplifier Class A Amplifiers are the simplest in design, and probably the best sounding of all the amplifier classes due to their low signal distortion. The class A amplifier has the highest linearity over the other amplifier classes and as such operates in the linear portion of the characteristics curve. This means that the output stage whether using a bipolar, mosfets or IGBT device, is never driven fully into its cut-off or saturation regions. Class A Amplifier To achieve high linearity and gain, the output stage is biased “ON” (conducting) all the time and operates at a constant current equal to or greater then the current which the load (usually a loudspeaker) requires to produce the largest output signal. The output device conducts through 360 degrees of the output waveform. Then the class A amplifier is equivalent to a current source. Since a class A amplifier operates in the linear region, the transistors base (or gate) DC biasing voltage should by chosen properly to ensure correct operation and low distortion. However, as the output device is “ON” at all times, it is constantly carrying current, which represents a continuous loss of power in the amplifier. Due to this continuous loss of power class A amplifiers create tremendous amounts of heat adding to their very low efficiency at around 30%, making them impractical for high-power amplifications. Therefore, due to the low efficiency and over heating problems of Class A amplifiers, more efficient amplifier classes have been developed. Class B Amplifier Class B amplifiers were invented as a solution to the efficiency and heating problems associated with the class A amplifiers. The basic class B amplifier uses two complimentary transistor devices (one NPN and one PNP transistor connected in common collector mode) in its output stage configured in a “push-pull” arrangement, with each device amplifying only half of the output waveform. In the class B amplifier, there is no standing bias current as its quiescent current is zero, therefore its efficiency is much higher than that of the class A amplifier. When the input signal goes positive, the positive biased device conducts while the negative device is switched off. Likewise, when the input signal goes negative, the positive device switches off while the negative biased device turns on and conducts the negative portion of the signal. Class B Amplifier Therefore, each transistor device of the class B amplifier only conducts through 180 degrees of the output waveform in strict time alternation, but as the output stage has devices for both halves of the signal waveform the two halves are combined together to produce the full linear output waveform. This push-pull design of amplifier is obviously more efficient than Class A, at about 50%, but the problem with the class B amplifier design is that it can create distortion at the zero-crossing point of the waveform due to the transistors dead band of input base voltages from -0.7V to +0.7V, making it unsuitable for precision amplifier applications. Class AB Amplifier As its name suggests, the Class AB Amplifier is a combination of the two class A and class B type amplifiers above, and is currently one of the most common types of power amplifier design. The class AB amplifier is a variation of a class B amplifier as described above, except that both devices are allowed to conduct at the same time around the crossover point eliminating the crossover distortion problems of the pure class B amplifier. The two transistors have a very small bias voltage, typically at 5 to 10% of the quiescent current to bias the transistors just above cut-off. In this case, the transistor will be “ON” for more than half a cycle, but less than a full cycle of the input signal. Then in a class AB amplifier design each of the push-pull transistors is conducting for slightly more than the half cycle of conduction in class B, but much less than the full cycle of conduction of class A. Class AB Amplifier The advantage of this small bias voltage is that the crossover distortion created by the class B amplifier characteristics is overcome, without the inefficiencies of a the class A amplifier design. So the class AB amplifier is a compromise between class A and class B in terms of efficiency and linearity, with efficiencies reaching about 50% to 60%. Class C Amplifier The Class C Amplifier design has the greatest efficiency but the poorest linearity of the classes of amplifiers. The previous classes, A, B and AB are considered linear amplifiers, as the output signals amplitude and phase are linearly related to the input signals amplitude and phase. However, the class C amplifier is heavily biased so that the output current is zero for more than one half of an input sinusoidal signal cycle. In other words, the conduction angle for the transistor is significantly less than 180 degrees, at around 90 to 120 degrees. This form of biasing gives a much improved efficiency of around 80% to the amplifier, but very heavy distortion of the output signal. Therefore, class C amplifiers are not suitable for use as audio amplifiers. Class C Amplifier Class C amplifiers are commonly used in high frequency sine wave oscillators and certain types of radio frequency amplifiers, where the pulses of current produced at the amplifiers output can be converted to complete sine waves of a particular frequency by the use of LC resonant circuits. Then we have seen that the quiescent DC operating point (Q-point) of an amplifier determines the amplifier classification. By setting the position of the Q-point at half way on the load line of the amplifiers characteristics curve, the amplifier will operate as a class A amplifier. By moving the Q-point lower down the load line changes the amplifier into a class AB, B or C amplifier. Then the class of operation of the amplifier with regards to its DC operating point can be given as: Amplifier Classes and Efficiency As well as audio amplifiers there are a number of high efficiency Amplifier Classes relating to switching amplifier designs that use different switching techniques to reduce power loss and increase efficiency. Some amplifier class designs listed below use RLC resonators or multiple power-supply voltages to reduce power loss.
  5. I learned about the basic electronic components by going to the library and reading books. I was just starting out. And I felt like a lot of the book explained everything in a difficult way. In this article I will give you a simple overview, with an explanation of the basic electronic components – what they are and what they do. The Most Common Basic Electronic Components These are the most common components: Resistors Capacitors LEDs Transistors Inductors Integrated Circuits Resistor I didn’t understand the resistor in the beginning. It didn’t seem to do anything! It was just there, consuming power. With time, I learned that the resistor is actually extremely useful. You’ll see resistors everywhere. As the name suggests, they resist the current. But you are probably wondering: What do I use it for? You use the resistor to control the voltages and the currents in your circuit. Some basic electronics components: LED in series with a battery and a resistor How? By using Ohm’s law. Let’s say you have a 9V battery and you want to turn on a Light-Emitting Diode (LED). If you connect the battery directly to the LED, LOTS of current will flow through the LED! Much more that the LED can handle. So the LED will become very hot and burn out after a short amount of time. But – if you put a resistor in series with the LED, you can control how much current going through the LED. In this case we call it a current limiting resistor. Capacitor You can think of a capacitor as a battery with very low capacity. You can charge and discharge it just like a battery. The capacitor is often used to introduce a time-delay in a circuit. For example to blink a light. It’s commonly used for removing noise, or making the supply voltage of a circuit more stable. Read more about the capacitor in this article: How Does A Capacitor Work? There are many capacitor types. Most commonly, we divide them into polarized and non-polarized capacitors. Light Emitting Diode (LED) A Light Emitting Diode – or LED for short – is a component that can give light. We use LEDs to give a visual feedback from our circuit. For example to show that the circuit has power. But, you can also used them to make cool light-show circuits. You see these components everywhere: In your laptop, on your mobile phone, on your camera, in your car +++ And you can find many different types of LEDs. A very common circuit to build as a beginner is the blinking light circuit. Transistor This is probably the hardest of the basic electronic components to understand. But don’t worry, it’s not that hard. A simple way is to look at the transistor as a switch controlled by an electrical signal. If you put about 0.7 volts between the base and the emitter, you turn it on. Note that this is true for NPN transistors. There are also other types, but worry about these later. But, instead of having just two states (ON or OFF), it can also be “a bit on” by controlling the current that goes through its base. A bit of current on the base produces a current of maybe 100 times more (depending on the transistor) through the Collector and Emitter. We can use this effect to build amplifiers. Inductor Inductors are a bit weird. It’s just a coil of wire – and you can make one yourself by making some loops out of a wire. Sometimes they’re wound around a metal core of some sort. They are often used in filters. I rarely use one actually, but when I wrote that in my article “What is an inductor?” a friend of mine reacted. See his response at the end of that article. Integrated Circuit An Integrated Circuit (IC) consists of many basic electronic components. It’s nothing mysterious or magical. It’s just an electronic circuit that has been shrunk to fit inside a chip. It could be an amplifier, it could be a microprocessor, it could be a USB to serial converter… It could be anything! To figure out what a specific IC does, you can read its datasheet. What to do next? Now, you know a bit about the basic electronic components. But don’t just read about it – take action and start building electronics:
  6. Light Emitting Diodes or LED´s, are among the most widely used of all the different types of semiconductor diodes available today. They are the most visible type of diode, that emit a fairly narrow bandwidth of either visible light at different coloured wavelengths, invisible infra-red light for remote controls or laser type light when a forward current is passed through them. The “Light Emitting Diode” or LED as it is more commonly called, is basically just a specialised type of diode as they have very similar electrical characteristics to a PN junction diode. This means that an LED will pass current in its forward direction but block the flow of current in the reverse direction. Light emitting diodes are made from a very thin layer of fairly heavily doped semiconductor material and depending on the semiconductor material used and the amount of doping, when forward biased an LED will emit a coloured light at a particular spectral wavelength. When the diode is forward biased, electrons from the semiconductors conduction band recombine with holes from the valence band releasing sufficient energy to produce photons which emit a monochromatic (single colour) of light. Because of this thin layer a reasonable number of these photons can leave the junction and radiate away producing a coloured light output. LED Construction Then we can say that when operated in a forward biased directionLight Emitting Diodes are semiconductor devices that convert electrical energy into light energy. The construction of a Light Emitting Diode is very different from that of a normal signal diode. The PN junction of an LED is surrounded by a transparent, hard plastic epoxy resin hemispherical shaped shell or body which protects the LED from both vibration and shock. Surprisingly, an LED junction does not actually emit that much light so the epoxy resin body is constructed in such a way that the photons of light emitted by the junction are reflected away from the surrounding substrate base to which the diode is attached and are focused upwards through the domed top of the LED, which itself acts like a lens concentrating the amount of light. This is why the emitted light appears to be brightest at the top of the LED. However, not all LEDs are made with a hemispherical shaped dome for their epoxy shell. Some indication LEDs have a rectangular or cylindrical shaped construction that has a flat surface on top or their body is shaped into a bar or arrow. Generally, all LED’s are manufactured with two legs protruding from the bottom of the body. Also, nearly all modern light emitting diodes have their cathode, ( – ) terminal identified by either a notch or flat spot on the body or by the cathode lead being shorter than the other as the anode ( + ) lead is longer than the cathode (k). Unlike normal incandescent lamps and bulbs which generate large amounts of heat when illuminated, the light emitting diode produces a “cold” generation of light which leads to high efficiencies than the normal “light bulb” because most of the generated energy radiates away within the visible spectrum. Because LEDs are solid-state devices, they can be extremely small and durable and provide much longer lamp life than normal light sources. Light Emitting Diode Colours So how does a light emitting diode get its colour. Unlike normal signal diodes which are made for detection or power rectification, and which are made from either Germanium or Silicon semiconductor materials, Light Emitting Diodes are made from exotic semiconductor compounds such as Gallium Arsenide (GaAs), Gallium Phosphide (GaP), Gallium Arsenide Phosphide (GaAsP), Silicon Carbide (SiC) or Gallium Indium Nitride (GaInN) all mixed together at different ratios to produce a distinct wavelength of colour. Different LED compounds emit light in specific regions of the visible light spectrum and therefore produce different intensity levels. The exact choice of the semiconductor material used will determine the overall wavelength of the photon light emissions and therefore the resulting colour of the light emitted. Types of Light Emitting Diode • Gallium Arsenide (GaAs) - infra-red • Gallium Arsenide Phosphide (GaAsP) - red to infra-red, orange • Aluminium Gallium Arsenide Phosphide (AlGaAsP) - high-brightness red, orange-red, orange, and yellow • Gallium Phosphide (GaP) - red, yellow and green • Aluminium Gallium Phosphide (AlGaP) - green • Gallium Nitride (GaN) - green, emerald green • Gallium Indium Nitride (GaInN) - near ultraviolet, bluish-green and blue • Silicon Carbide (SiC) - blue as a substrate • Zinc Selenide (ZnSe) - blue • Aluminium Gallium Nitride (AlGaN) - ultraviolet IC Driver Circuit If more than one LED requires driving at the same time, such as in large LED arrays, or the load current is to high for the integrated circuit or we may just want to use discrete components instead of ICs, then an alternative way of driving the LEDs using either bipolar NPN or PNP transistors as switches is given below. Again as before, a series resistor, RS is required to limit the LED current. Transistor Driver Circuit The brightness of a light emitting diode cannot be controlled by simply varying the current flowing through it. Allowing more current to flow through the LED will make it glow brighter but will also cause it to dissipate more heat. LEDs are designed to produce a set amount of light operating at a specific forward current ranging from about 10 to 20mA. In situations where power savings are important, less current may be possible. However, reducing the current to below say 5mA may dim its light output too much or even turn the LED “OFF” completely. A much better way to control the brightness of LEDs is to use a control process known as “Pulse Width Modulation” or PWM, in which the LED is repeatedly turned “ON” and “OFF” at varying frequencies depending upon the required light intensity of the LED.