Week 6

 Title of Activity :  Components specifications and descriptions

Objective : To know with more details about the components

Content/ Procedure :

    This week, we continued with another components specifications and descriptions. Below, are show the pictures of components that I used in my project later.

Zero insertion force socket

      Zero insertion force (ZIF) is a concept used in the design of IC sockets and electrical connectors invented to avoid problems caused by applying force upon insertion and extraction.
A normal integrated circuit (IC) socket requires the IC to be pushed into sprung contacts which then grip by friction.

 For an IC with hundreds of pins, the total insertion force can be very large (tens of newtons), leading to a danger of damage to the device or the circuit board. Also even with relatively small pin counts each extraction is fairly awkward and carries a significant risk of bending pins (particularly if the person performing the extraction hasn't had much practice or the board is crowded). Low insertion force (LIF) sockets reduce the issues of insertion and extraction but the lower the insertion force of a conventional socket, the less reliable the connection is likely to be.

With a ZIF socket, before the IC is inserted, a lever or slider on the side of the socket is moved, pushing all the sprung contacts apart so that the IC can be inserted with very little force (generally the weight of the IC itself is sufficient with no external downward force required). The lever is then moved back, allowing the contacts to close and grip the pins of the IC. ZIF sockets are much more expensive than standard IC sockets and also tend to take up a larger board area due to the space taken up by the mechanism. Therefore they are only used when there is a good reason to do so.

Large ZIF sockets are only commonly found mounted on PC motherboards (from about the mid 1990s forward). These CPU sockets are designed to support a particular range of CPUs, allowing computer retailers and consumers to assemble motherboard/CPU combinations based on individual budget and requirements. The rest of the electronics industry has largely abandoned sockets and moved to surface mount components soldered directly to the board.

Smaller ZIF sockets are commonly used in chip-testing and programming equipment, e.g. programming and testing on EEPROMs, Microcontrollers, etc.

Universal test sockets

      Standard DIP packages come in two widths (measured between pin centers), 0.3 in (7.62 mm) (skinny dip) for smaller devices (8-28 pin) and 0.6 in (15.24 mm) for larger devices (24-40 pin). To allow design of programmers and similar devices that supported a range of devices some in skinny dip and some in full width dip universal test sockets are produced. These have wide slots into which the pins drop allowing both 0.3 in and 0.6 in devices to be inserted.

  

Ball grid array sockets

   ZIF sockets can be used for ball grid array chips, particularly during development. These sockets tend to be unreliable, failing to grab all the balls. Another type of BGA socket, also free of insertion force but not a "ZIF socket" in the traditional sense, does a better job by using spring pins to push up underneath the balls.

ZIF wire-to-board connectors

    ZIF wire-to-board connectors are used for attaching wires to printed circuit boards inside electronic equipment. The wires, often formed into a ribbon cable, are pre-stripped and the bare ends placed inside the connector. The two sliding parts of the connector are then pushed together, causing it to grip the wires. The most important advantage of this system is that it does not require a mating half to be fitted to the wire ends, therefore saving space and cost inside miniaturised equipment.

Hard disk drives

  ZIF tape connections are used for connecting IDE and SATA disk drives (mostly 1.8" factor). ZIF-style connectors for IDE hard drives were used primarily in the design of Ultra-Portable notebooks, and has since been phased out, as SATA has a relatively small-form-factor connector by default. Also, nearly all hard drives use ZIF tape to connect their circuit board to their platter motor.

 Three types of ZIF connectors are known to exist on 1.8" drives. ZIF-24, ZIF-40, and ZIF-50 with 24, 40, and 50 pins respectively. ZIF tape connections are also heavily used in the design of the Apple Inc. iPod range of portable media players.

PCB UV Board 

 Push button and switch 

    Structure of a vacuum tube diode   

Diode

  In electronics, a diode is a type of two-terminal electronic component with nonlinear resistance and conductance ( nonlinear current–voltage characteristic), distinguishing it from components such as two-terminal linear resistors which obey Ohm's law. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material connected to two electrical terminals. A vacuum tube diode (now rarely used except in some high-power technologies) is a vacuum tube with two electrodes a plate and a cathode.

The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction). Thus, the diode can be thought of as an electronic version of a check valve. This unidirectional behavior is called rectification, and is used to convert alternating current to direct current, and to extract modulation from radio signals in radio receivers.

However, diodes can have more complicated behavior than this simple on–off action. Semiconductor diodes do not begin conducting electricity until a certain threshold voltage is present in the forward direction. The voltage drop across a forward-biased diode varies only a little with the current, and is a function of temperature; this effect can be used as a temperature sensor or voltage reference.

Semiconductor diodes' nonlinear current–voltage characteristic can be tailored by varying the semiconductor materials and introducing impurities into (doping) the materials. These are exploited in special purpose diodes that perform many different functions. For example, diodes are used to regulate voltage (Zener diodes), to protect circuits from high voltage surges (avalanche diodes), to electronically tune radio and TV receivers (varactor diodes), to generate radio frequency oscillations (tunnel diodes, Gunn diodes, IMPATT diodes), and to produce light (light emitting diodes). Tunnel diodes exhibit negative resistance, which makes them useful in some types of circuits.

Oscillator

Oscillator

   An electronic oscillator is an electronic circuit that produces a repetitive electronic signal, often a sine wave or a square wave. They are widely used in many electronic devices. Common examples of signals generated by oscillators include signals broadcast by radio and television transmitters, clock signals that regulate computers and quartz clocks, and the sounds produced by electronic beepers and video games.

Oscillators are often characterized by the frequency of their output signal which is an audio oscillator produces frequencies in the audio range, about 16 Hz to 20 kHz. An RF oscillator produces signals in the radio frequency (RF) range of about 100 kHz to 100 GHz. A low-frequency oscillator (LFO) is an electronic oscillator that generates a frequency below ≈20 Hz. This term is typically used in the field of audio synthesizers, to distinguish it from an audio frequency oscillator.

Oscillators designed to produce a high-power AC output from a DC supply are usually called inverters.
There are two main types of electronic oscillator which are the harmonic oscillator and the relaxation oscillator.

 Capacitor

 Capacitor

   A capacitor (formerly known as condenser) is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric (insulator); for example, one common construction consists of metal foils separated by a thin layer of insulating film. Capacitors are widely used as parts of electrical circuits in many common electrical devices.

When there is a potential difference (voltage) across the conductors, a static electric field develops across the dielectric, causing positive charge to collect on one plate and negative charge on the other plate. Energy is stored in the electrostatic field. An ideal capacitor is characterized by a single constant value, capacitance, measured in farads. This is the ratio of the electric charge on each conductor to the potential difference between them.

The capacitance is greatest when there is a narrow separation between large areas of conductor, hence capacitor conductors are often called "plates," referring to an early means of construction. In practice, the dielectric between the plates passes a small amount of leakage current and also has an electric field strength limit, resulting in a breakdown voltage, while the conductors and leads introduce an undesired inductance and resistance.

Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuits that tune radios to particular frequencies, in electric power transmission systems for stabilizing voltage and power flow, and for many other purposes.

Ceramic capacitor 

Ceramic capacitor  

   In electronics, a ceramic capacitor is a capacitor constructed of alternating layers of metal and ceramic, with the ceramic material acting as the dielectric. The temperature coefficient depends on whether the dielectric is Class 1 or Class 2. A ceramic capacitor (class 2) often has high dissipation factor, high frequency coefficient of dissipation.
A ceramic capacitor is a two-terminal non-polar device. The classical ceramic capacitor is the "disc capacitor". This device pre-dates the transistor and was used extensively in vacuum-tube equipment (radio receivers) from about 1930 through the 1950s, and in discrete transistor equipment from the 1950s through the 1980s. As of 2007, ceramic disc capacitors are in widespread use in electronic equipment, providing high capacity and small size at low price compared to other low value capacitor types.
Ceramic capacitors come in various shapes and styles, including:

• disc, resin coated, with through-hole leads
• multilayer rectangular block, surface mount
• bare leadless disc, sits in a slot in the PCB and is soldered in place, used for UHF applications
• tube shape, not popular now

Classes of ceramic capacitors

Class I capacitors:  accurate, temperature-compensating capacitors. They are the most stable over voltage, temperature, and to some extent, frequency. They also have the lowest losses. On the other hand, they have the lowest volumetric efficiency. A typical class I capacitor will have a temperature coefficient of 30 ppm/°C. This will typically be fairly linear with temperature. 

Class II capacitors:  better volumetric efficiency, but lower accuracy and stability. A typical class II capacitor may change capacitance by 15% over a −55 °C to 85 °C temperature range. 

Class III capacitors:  high volumetric efficiency, but poor accuracy and stability. A typical class III capacitor will change capacitance by -22% to +56% over a temperature range of 10 °C to 55 °C. These are typically used for decoupling or in other power supply applications.

At one point, Class IV capacitors were also available, with worse electrical characteristics than Class III, but even better volumetric efficiency. They are now rather rare and considered obsolete, as modern multilayer ceramics can offer better performance in a compact package.

Nine-volt battery

 

 Nine-volt battery

 The most common form of nine-volt battery is designated NEDA 1604, IEC 6LR61 or U.K. "Ever Ready" type PP3. The battery is a rectangular prism shape with rounded edges and a polarized snap connector at the top.

This type is commonly used in pocket transistor radios, smoke detectors, carbon monoxide alarms, guitar effect units, and radio-controlled vehicle controllers. They are also used as backup power to keep the time in certain electronic clocks. This format is commonly available in primary carbon-zinc and alkaline chemistry, in primary lithium iron disulfide, and in rechargeable form in nickel-cadmium and nickel-metal hydride types.

Mercury oxide batteries in this form have not been manufactured in many years due to their mercury content.
Nine-volt alkaline batteries are constructed of six individual 1.5V LR61 cells enclosed in a wrapper. These cells are slightly smaller than standard LR8D425 AAAA cells and can be used in their place for some devices, even though they are 3.5 mm shorter.

Resistor

Resistor

   A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. The current through a resistor is in direct proportion to the voltage across the resistor's terminals. Thus, the ratio of the voltage applied across a resistor's terminals to the intensity of current through the circuit is called resistance. 

Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors can be made of various compounds and films, as well as resistance wire (a high-resistivity alloy, such as nickel-chrome). Resistors are also implemented within integrated circuits, particularly analog devices, and can also be integrated into hybrid and printed circuits.

The electrical functionality of a resistor is specified by its resistance: common commercial resistors are manufactured over a range of more than nine orders of magnitude. When specifying that resistance in an electronic design, the required precision of the resistance may require attention to the manufacturing tolerance of the chosen resistor, according to its specific application.

The temperature coefficient of the resistance may also be of concern in some precision applications. Practical resistors are also specified as having a maximum power rating which must exceed the anticipated power dissipation of that resistor in a particular circuit: this is mainly of concern in power electronics applications. Resistors with higher power ratings are physically larger and may require heat sinks.

In a high-voltage circuit, attention must sometimes be paid to the rated maximum working voltage of the resistor. Practical resistors have a series inductance and a small parallel capacitance. In a low-noise amplifier or pre-amp, the noise characteristics of a resistor may be an issue. The unwanted inductance, excess noise, and temperature coefficient are mainly dependent on the technology used in manufacturing the resistor. They are not normally specified individually for a particular family of resistors manufactured using a particular technology. A family of discrete resistors is also characterized according to its form factor, that is, the size of the device and the position of its leads (terminals) which is relevant in the practical manufacturing of circuits using them.

Variable resistor 

Potentiometer/ variable resistor

   A variable resistor is a potentiometer with only two connecting wires instead of three. However, although the actual component is the same, it does a very different job. The pot allows us to control the potential passed through a circuit. The variable resistance lets us adjust the resistance between two points in a circuit.

   A variable resistance is useful when we don't know in advance what resistor value will be required in a circuit. By using pots as an adjustable resistor we can set the right value once the circuit is working. Controls like this are often called 'presets' because they are set by the manufacturer before the circuit is sent to the customer. They're usually hidden away inside the case of the equipment, away from the fingers of the users! 

 LDR

Light Dependent Resistors

 

   LDRs or Light Dependent Resistors are very useful especially in light/dark sensor circuits. Normally the resistance of an LDR is very high, sometimes as high as 1000 000 ohms, but when they are illuminated with light resistance drops dramatically. 

The animation opposite shows that when the torch is turned on, the resistance of the LDR falls, allowing current to pass through it.

  When a light level of 1000 lux (bright light) is directed towards it, the resistance is 400R (ohms). When a light level of 10 lux (very low light level) is directed towards it, the resistance has risen dramatically to 10.43M (10430000 ohms).     

LED

 
Light-emitting diode

   A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Introduced as a practical electronic component in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness.

When a light-emitting diode is forward-biased (switched on), electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence and the color of the light (corresponding to the energy of the photon) is determined by the energy gap of the semiconductor. LEDs are often small in area (less than 1 mm2), and integrated optical components may be used to shape its radiation pattern.

 LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, and faster switching. LEDs powerful enough for room lighting are relatively expensive and require more precise current and heat management than compact fluorescent lamp sources of comparable output.

Light-emitting diodes are used in applications as diverse as aviation lighting, automotive lighting, advertising, general lighting, and traffic signals. LEDs have allowed new text, video displays, and sensors to be developed, while their high switching rates are also useful in advanced communications technology. Infrared LEDs are also used in the remote control units of many commercial products including televisions, DVD players, and other domestic appliances.

Result and analysis :

Students should be able in knowing all components specifications and descriptions.

Conclusions :  

This week, with this all informations, can gain our knowledge in detail knowing the basic electronics components for circuit. From the descriptions and specifications that I gives, also will help us later on in future and present especially when working in medical electronics field. I hope that this project can be commercialized in medical electronics field especially in hospitals, medical suppliers, universities, students and so on. Insya Allah.