Wednesday, December 4, 2019

The Perils of Obedience by Stanley Milgram free essay sample

In â€Å"The Perils of Obedience,† Stanley Milgram develops a experiment that puts to test the the question , â€Å"Will humans inflict extreme pain to others under the command of higher authority? †. The essay starts off with Milgram explaining the history of obedience by exhibiting the loyalness that was portrayed by followers in historical documents. The experiment that Milgram set up was simple. He elected an â€Å"experimenter† who is the authority figure, a â€Å"teacher† which is the subject of the experiment, and a â€Å"learner† whose only obligation is to act as if s/he is in pain. The teacher in the experiment reads off a simple list of words, and the student must remember the second word of a pair upon hearing the first one again. If the student is wrong, the teacher must inflict pain on the student, increasing the pain each time the student makes an error. Before actually conducting these experiments, Milgram asked for predictions from various groups of people. We will write a custom essay sample on The Perils of Obedience by Stanley Milgram or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page It was predicted that almost all the subjects would deny to obey the experimenter, but these predictions were proved wrong. In the first group of subjects, only 25 of the 40 who participated in the experiment obeyed all the orders from the experimenter. In another scenario where Yale undergraduates were used as subjects, 60 percent of them were obedient to the experimenter. In the first experiment that Milgram conducts, the subject Gretchen Brandt defies the experimenters request by refusing to inflict anymore pain on the student because of the immoral pain that she believed the student was in. This is the response that Milgram initially thought would be for all subjects. In the second experiment that Milgram conducted, his subject Fred Prozi, was obedient to the experimenter, although he clearly did not want to cause any harm to the learner, Prozi respected the authority that the experimenter showcased. Each time Prozi insisted that the experiment be stopped , the experimenter would demand that he go on, and he did. Milgram’s most memorable subject, Morris Braverman, was unlike the other subjects who participated in this experiment because he showed signs of enjoyment during the experiment. Braverman strictly followed the experimenters orders, and also laughed at times when he administered pain to the learner. Later in the essay, Milgram begins to explain why subjects responded to the experiments the way that they did stating that â€Å"all people harbor deeply aggressive instincts† (77). He also stated that subjects gained more satisfaction with pleasing the experimenter and doing a good job, than actually caring for the well being of the learner. One notable subject, Bruno Batta, made sure that the experiment went as planned, even going as far as forcing the learners hand back onto the shock plate . Milgram refers to Hannah Arendt’s book Eichmann in Jerusalem, in which Arendt states that the horrible deeds that Eichmann carried out did not make him a monster, because he was only being obedient towards higher authority. The experiments that Milgram constructed proved that most humans will inflict pain to others under the command of a higher authority.

Wednesday, November 27, 2019

Human development Essay Example

Human development Essay The purpose of this paper is to think of a particular time In my childhood and apply Brotherlinesss five systems to that particular time. Erie Brotherlinesss ecological theory in child development suggest that five levels of the environment simultaneously influences us as children. Frontbencher believes that we cannot fully understand the phenomenon of continuity and bio-psychological characteristics of a child without considering how we are influence by each level of our environment. The 5 levels he mentions are, Microsystems, Microsystems, Ecosystem, Microsystems and Chronometers (Feldman 2011). I grew up on the island of Montmartre which is a British territory, where the environment helped shape who I am today, I moved to the united states when I was 13 years old, where I realized that life there was much different than what I was accustom to, for I no longer had the support from the community and family members I had grown so accustomed to. This is why I found Brotherlinesss biological approach so interesting because it reminded me Just how much I had lost and how much I had achieved. The particular time period In my childhood that I would like to discuss in this essay is when I was about 10 years old. I chose this time period due to the fact that this was a time when life changed for my family and me in more ways than one, in some ways positive but in many ways negative. The most serious Impact on my life occurred at the age of 10 years old, which I will be discussing in detail further on in this essay. We will write a custom essay sample on Human development specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Human development specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Human development specifically for you FOR ONLY $16.38 $13.9/page Hire Writer According to my reading the Microsystems is defined as the everyday immediate environment in which we lead our lives. (Feldman 2011). In my case the immediate environment at that time were my friends, teachers, brothers, and the community, they were part of the long-term Immediate environment In which I placed my trust, other temporary Microsystems that came and went are athletic clubs, boy scouts, and church, through those Microsystems I got a chance to build relationships, built various skills, and I also learned how to socialize through personal experience. At about age 10 1 developed a love for track and field and went on to win numerous medals In school which Is a personal success story of mine. In this period in time I could remember my family was close, but at the same time, having regular arguments and fights, I thought thing of It at the time, for I would Join the arguments to defend my mother in particular. I didnt have a father In my life so my mother was the one that took care of me, not having a father in the picture was not a good experience for me, I think this is why I was so close with my mother. My brothers I could remember were always there willing to teach what they knew, there were times when I wanted to be like my older brothers. I was younger than they were but we would socialize Like we were friends we, had a good relationship, through my brothers I learned how to act in school, all of those social interactions were crucial to my development. My family had the same problems like every other family but I felt protected surrounded by them. My mother and grandfather were always arguing, I would try to defend my mother of course. At age 10 1 could remember going to school, I was already tough because of what I learned from my brothers, I got in all sorts of fights with the other students but 1 OFF around. The teachers in the school were strict, they were allowed to use corporal punishment, so I would often get punished for not doing homework, fighting, and arioso other reasons. My peers at the time from what I could remember were tough. My community I would describe as been close, the community demanded respect, I could not pass someone without saying good day or good morning or I would be punished. The Microsystems refers to all the settings in which a child personally interacts and is influenced, so in my case my Microsystems are family, athletic clubs, and children in the community. All of those personal social interactions are what influenced me at the time, and which, makes up one of the 4 system of Brotherlinesss which is the Microsystems. According to the reading the Microsystems provides connections between various aspects of the Microsystems, the Microsystems binds children to parents, students to teacher and friends to friends (Feldman 2011). When two Microsystems come together, they form a Microsystems, most time a unique and positive experience is created, but other times you have confusion and stress on the child. My mother had minimal interactions with my peers but when my peers would come to my house she would interact with them, she had different rules in the house so there were often confusion, for example no eating n the living room, and no swearing in the house, this was due to the fact that two Microsystems came together creating a rift between acceptable behavior. She was very involved in my school affairs, she knew most of the teachers personally so she interacted with them on a regular basis, I would go as far as to say she was friends with a lot of the teachers at the school, all of the teachers were from the community, I couldnt hide exam results, or if I failed to do my homework the teachers knew her personally so they would call her. By bringing teacher and my parent together a ecosystem was created, the interaction between my parent and teacher showed me that they were interested in how well I was doing in school and was united in making sure I did my best. My mother was particularly strict and persistent when it came to me doing my homework, she would stay up all night if she had to, to help me with my homework and if I didnt do my homework and she found out I would be punished. I was involved in athletics throughout my school life and the community would be there to cheer on the children, so they were very engaged in our sports activities, because the community was small everyone knew each other personally from searchers, members of the community and friends, we all had a type of bond linking us together, if one person died we would all feel it. I would say that the Microsystems had a positive influence on me because it provide me the social support and consistency in practically every activity I took part in at that time. If I am correct my ethnic heritage is afro-Caribbean, am affiliated with the Christian church. At 10 years old I was not too familiar with what was going on in the rest of the world, there were murmurs of war overseas, but I was only 10 it didnt register to me or mean anything to me at the time. At that time I was influence by the Christian religion and the church, for my mother was adamant about us going to church every Sunday. According to the reading the macro system represents the larger cultural influences on an individual for example society, types of government, religious and political value system and other broad, encompassing factors are part of the macro system religious beliefs, or political views which are part of the macro system. According to my reading the Ecosystem represent broader influence, encompassing social institution such as local governments, the community, schools, places of worship and he local media (Feldman, 2011). My mother was the secretary of the secondary school on the island, I do not think I took any vacation at that age, my mother was a single parent and was never married, and there was no father in the picture. I could remember when my mother my went away for a long time and I had to stay with friends and relatives, I had to live under a set of different rules I felt that the love that I had from family around me no longer existed, things changed for that time period I didnt have my peers, or teachers around, this created confusion and I became assistant. I would say the single historical event that effected my development at that time was the volcanic eruption that destroyed my island. When the volcano erupted everything changed, my school life was over, a lot of the influential people left the island, and my school was transformed into a shelter, so I was forced to leave for the United States. According to my reading the chronometers involves the way the passage of time historical events affect ones development (Feldman 2014). Due to the eruption I had to live under different rules, go to a new in school, find new friends ND live in the new household, I became a different person due to that event.

Sunday, November 24, 2019

Lights! Camera! Action! Marin Luther and Reformation

Lights! Camera! Action! Marin Luther and Reformation Is Martin Luther due all the credit given him for the genesis of the Reformation? Perhaps, but one has to look at a few other factors that certainly set the stage for Luther. Hardly ever does one person come along and, without any preparation, change the cultural traditions let alone a whole world.Sometimes a leader is just lucky; the timing is right. For Martin Luther to reform religion it took a bit more than just luck. It took intelligence, skillfulness, and education. Martin Luther had all three of these and the luck of timing. There were, however, some people and events that set the stage for Luther and the reformation movement. The humanistic movement was one, very important factor.Humanism already had strong, healthy roots in Western Europe and was the philosophy under which Martin Luther studied. It could be said that this movement was the true ignition of reformation although without Luther to fan its flames, reformation would have taken many more years to become the fire th at burned through Catholicism with a vengeance.Martin Luther, commemorated on February 18 Evangel...Aside from the humanist movement there were a few men: John Wiclif, Jan Hus, and Erasmus would play important roles in the very beginning before Martin Luther‚s time. Between these three men: biblical translations, teachings that the bible was for the individual, questioning authority, ridicule of the gross misconduct and improprieties of the papacy, and martyrdom can be found. (Greer 409-412) These acts are not to be ignored when contemplating the foundation of reformation.With the acts of these three men, all the props on Martin Luther‚s stage were in place. The bible became accessible to all members of the congregation, and reading it was strongly encouraged. Erasmus showed that the papacy was not only to be wrong, but ridiculously so.

Thursday, November 21, 2019

IT Research Paper Example | Topics and Well Written Essays - 1250 words

IT - Research Paper Example Thus, it is advised by computer experts to keep a backup of the information and resources that are stored on computer systems. This paper will focus upon the various storage devices that can be used by computer users to keep a backup of their information and resources, and the differences between redundant and backup data storage and how systems fail and how can they be protected. Backup Media Various forms of backup media available to users include: optical storage methods such as writeable and re-writable CDs and DVDs, external and internal hard disks that can be mounted on the systems and flash memory systems such as pen drives, USB drives and memory cards. Information stored on optical drives can last for very long period of time if these drives are kept safely, secondly these drives are even available in write once only form. This is an advantage because the data that is stored on these drives cannot be replaced or over-written. These drives even come in re-writable form; this m eans that same drive can be used do over write if old information is no longer needed. These drives are easy to move from one pc to another, these drives can be used in several systems but one system can use it at a time. Another downside of optical drives is that the time taken by these drives to write data and store information on them is considerably high if compared to the time taken by flash drives and other forms of memory drives. Another form of backup media that can come in handy for computer users is installing a second hard drive internally or externally. The advantages of having a second hard disk are enormous. Firstly, the second hard disk can act as a backup for files stored on your system; this will come in handy if the files from the first hard disk are deleted. Another advantage of using an extra hard disk is that the process of backing up files in a second hard disk is faster as compared to backing up these files in an optical drive or a USB flash memory drive. Havi ng a second hard disk is even of advantage as the files and the resources that have been downloaded over time on the computer system can be safe and the users d not have to take the pain of downloading and saving these resources again. All the operations conducted in a computer system take place on the first hard disk or the primary hard disk, due to this continuous usage, the hard disk becomes old and starts wearing out and ultimately the user has to replace it. When two hard disks are involved in the process of running a computer system, the burden of running the computer system is shared and both the hard disks gain higher functional life time. Disadvantages associated with installing a second hard disk are few in number. Firstly, hard disks have to be dealt with extra care, misuse may easily damage or corrupt the hard disk and data loss may occur, secondly, if the drive is installed inside the system, moving the drive to another system might become difficult and during the trans fer, the chances of damage are quite high. One of the best backup media designed to-date is USB flash memory drives/sticks. The advantages of using this media are: they are very small in size and can hold huge amount o information, they are easy to move and do not contain parts that might get corrupted if they are mishandled. These drives are even better than optical drives as they cannot be destroyed due to scratches and dust. Installing them is much easier than installing hard disks as they do not need

Wednesday, November 20, 2019

Critical analyse the paper's purpose Assignment

Critical analyse the paper's purpose - Assignment Example It then examines the causative factors using the hypothetical testing model before making recommendation projected to help educators curb the menace. According to Guo (2011), the key factors leading to plagiaristic behaviors include moral capability, awareness, and academic integration, accounting education, pressures, new technology, institutional support, cultural influences and demographic variables. These hypothesized factors were put into a conceptual model in order to test and ascertain or disqualify them as causative agents as well as to identify any connections among them through a series of questionnaires analysis. The questionnaire was divided in three sections depending on the hypothesized factors, extent of the plagiarism and the demographic factors relating to the respondents. The findings indicated a high degree of co-relation between the hypothesized constructs producing many statistically significant connections which were broadly consistent with the hypothesis. Never theless, research findings were surprising since new technology failed to relate to other constructs and the results were inconsistent with past studies creating a gap that needs to be addressed through further research (Guo 2011). Finally, the paper recommends that educators should take into consideration the effects of student’s cultural background on their propensity to plagiarize; in addition, to focusing on the ethic centric models of learning and integrate students into their academic life. The study sets out to examine students awareness of plagiarism and concludes that some of them ignore the concept altogether because they do not appreciate its gravity as an offence. While others use sources and share information among each other, but do not understand at what point using sources can turns into plagiarism (Granitz & Loewy 2001). Students who are not well integrated in the school system tend to plagiarize more often as an attempt to fit in the system. Moreover, variou s pressure thrust upon accounting students such as parental expectations, especially if they fund the student’s education my also increase a student’s propensity for plagiarism. Similarly, the rigours associated with accounting exams in the UK especially because of the many exam bodies tend to intimidate students and forces them to find easy way out through plagiarizing (Renard 2000). Analysing from a demographic standpoint, the study show that male students are more likely to cheat than female ones; additionally, high rate of plagiarism among students was suggested to be inversely proportional to age with younger scholars being more prone to cheating. Technology was also found to have a positive relationship with plagiarism owing to the wealth of data available on the internet, which students can access and apply in their work with hardly any reading involved. The solution to technology based plagiarism presents a complex situation despite the fact that the tools and software required to address the problem can be found in the same technology (Evans 2006). Currently, many institutions apply plagiarism-detecting tools like turnitin to ensure they police their students’ essays and discourage the vice (Mulcahy & Goodacrep 2004). Notwithstanding, students can still counter this by either using one of an assortment of online software that can paraphrase their essays and prevent detection through

Sunday, November 17, 2019

Let's Be Lefties For a Day Assignment Example | Topics and Well Written Essays - 500 words

Let's Be Lefties For a Day - Assignment Example ch ensures that employees maximize their contribution to the organization while enabling them to reach their own potential; creating a win-win situation for all. Diversity in the workplace refers to the variety of employees in a given work environment. Every organization today is made up of employees from a variety of ethnic, cultural, and racial backgrounds, add to this diverse group a mix of genders. Managers and professionals in such settings are responsible for molding this diverse group into a cohesive unit that benefits the organization, while ensuring that every employee is enabled to reach his/her potential. The idea of diversity is acceptance of differences and respect for them. In essence this means accepting that each individual is unique and is different from another in certain respects. These differences can be in a wide variety of spheres ranging from cultural and racial to religious and gender. Exploring these dimensions and understanding them can lead to an enriching experience – the ability to not just make allowances for but to appreciate them and celebrate the unique qualities they contribute. Diversity does not mean just physical diversity in outward appearance or speech. People who grow up in differing environments or come from different educational backgrounds also think and respond differently. The difference lies not only in how they are perceived but also how they perceive others and themselves. This also affects the way they interact with others especially those they perceive to be different from themselves. The result can be discrimination where those who ‘belong’ are at an advantage while those who do not are at a disadvantage. The challenge for the manager or professional in a business setting is to build bridges across differences and strengthen bonds to enable a work environment sans discrimination. The simple experiment of using the left hand instead of the right for ordinary activities like turning the pages of a book or

Friday, November 15, 2019

Home Appliances Control Using RF

Home Appliances Control Using RF The project HOME APPLIANCES CONTROL USING RF is an alternate of the job done by human like switch on/off by hand. Here job of doing on/off can be done by from a distance by help of remote. The ckt. Consists of four parts. These are listed below:- Power supply of 5v and 9v:- it consist of ic 7805,7809 , two transformer, capacitors and diode. Microcontroller:- it consists of m/c AT89S52 , reset ckt. RF module:- It consists of ic HT-12D AND HT-12E relay part:- two ralays, two diode,two bulbs ref.(1) HISTORY In this rf based project our data to control home appliance is send from remote to control them, here user only have to press the switch of remote. In other words, one could remotely turn on light in ones lawn or the air conditioning at home, or turn on/off the light of room by help of remote sitting at one palace in home, The operation cost and power required is also less. METHODOLOGY In this project our signal is transmitted through air from RF transmitter to RF receiver, which decoded the signal received, now decoded signal is send by 4 line to microcontroller. Microcontroller do the work on received data according to programming, which will turn on/off the relays, then bulbs are also on/off. BLOCK DIAGRAM Fig.1 Ref(5) CIRCUIT DIAGRAM Fig. 2 Ref(5) Fig. 3 Ref.(5) WORKING There are two power supplies one of 5v and second of 9v. Power supplies are made by bridge wave rectifier. For making 5v supply we use 4doide, one capacitor of 470 micro F, ic regulator 7805, similarly the second power supply. 5v supply is given to AT89S52 and 9V to operate the relay. Firstly the rf signal is generated by ic HT-12E and transmitted through air by help of rf transmitter module, the received data is now decoded by rf ic HT-12D and send to microcontroller to work on it. Some connections are made be ready the functioning of both ics. When signal is decoded by ic HT-12D it gives output by its pin no. 10 to 13. These output lines feed to m/c to pin no. 10 to 13 to make the m/c in action some connection are made as shown in fig of ckt.(Reset ckt. At pin no. 9, oscillator of value 11.0592 at pin no. 18 and 19 and power at pin no 40) Now, button of remote is pressed by user then m/c do low or high to the pin no p2.0 and p2.1 output line from m/c connected to TIP 122 base. These are high power transistor whose base is connected to to pin no p2.0 and p2.1 of m/c through resistance. If high power is given to TIP than it will be on due to which the relay make the connection between 3 and 4, and bulb be on. If low is at base of TIP then TIP will not work and connection of relay will be 3 and 4 due to which bulb be off. So we can do on/off the home appliance by help of remote. In our project one bulb be on by pressing button 1, second by help of 2, both will be on by button no. 3. And both will be offed by button no. 4. Ref.(6) APPLICATION By using home appliance control using rf we can control all the electrical devices of a home with the help of remote. We can on/off the devices by a distance. With the help of this concept we can make a robotic hand to handle the objects which a far away from us. With this we can also design car whose motion can be controlled by a remote. For a specific movement of car we will define a specific command for forward movement we will press button no. 1 for backward button no. 2 for left by help of button no. 3 and right by button by help of button no. 4 Other applications Burglar alarm system Smoke and fire alarm system Garage door controllers Car door controllers Car alarm system Security system Cordless telephones Other remote control systems Ref(5) PROBLEMS While controlling home appliances using RF we have to face some following problems:- We have used it to a particular range abt. of some meters not in range of kilometer or more distance. If m/c hanged we want to do on/off the switch then we are not confirmed abt. its on/off states. CONCLUSION This project is very useful for electricity saving purpose. Because we can do on/off the switch very quickly, otherwise due to laziness we avoid to on/off them. Project can easily be used by any one because to use this project one should not need to learn any special things and this project is very economical due to its simple circuit and by use of cheap components. COMPONENTS LIST Serial no. Component Specifications Quantity 1 Transformer 1amp,12v 1 2 Regulator7805 1 3 Regulator 1 4 Transformer 1amp,9v 1 5 TIP 122 2 6 Diodes IN 4001N 8 7 RELAY 2 8 MICROCONTROLLER AT 89S52 1 9 HT-12D 1 10 HT-12E 1 COMPONENT DETAILS MICROCONTROLLER AT89S52:- Fig. 4 ref(3) The Intel AT89S52 is a Harvard architecture, single chip microcontroller (ÂÂ µC) which was developed by Intel in 1980 for use in embedded systems. It was popular in the 1980s and early 1990s, but today it has largely been superseded by a vast range of enhanced devices with AT89S52-compatible processor cores that are manufactured by more than 20 independent manufacturers including Atmel, Infineon Technologies, Maxim Integrated Products (via its Dallas Semiconductor subsidiary), NXP (formerly Philips Semiconductor), Winbond, ST Microelectronics, Silicon Laboratories (formerly Cygnal), Texas Instruments and Cypress Semiconductor. Intels official designation for the AT89S52 family of ÂÂ µCs is MCS 51. Intels original AT89S52 family was developed using NMOS technology, but later versions, identified by a letter C in their name, e.g. 80C51, used CMOS technology and were less power-hungry than their NMOS predecessors this made them eminently more suitable for battery-powered devices Important features and applications:- It provides many functions (CPU, RAM, ROM, I/O, interrupt logic, timer, etc.) in a single package 8-bit data bus It can access 8 bits of data in one operation (hence it is an 8-bit microcontroller) 16-bit address bus It can access 216 memory locations 64 kB each of RAM and ROM On-chip RAM 128 bytes (Data Memory) On-chip ROM 4 kB (Program Memory) Four byte bi-directional input/output port UART (serial port) Two 16-bit timers Two-level interrupt priority Power saving mode A particularly useful feature of the AT89S52 core is the inclusion of a boolean processing engine which allows bit-level boolean logic operations to be carried out directly and efficiently on internal registers and RAM. This feature helped to cement the 8051s popularity in industrial control applications. Another valued feature is that it has four separate register sets, which can be used to greatly reduce interrupt latency compared to the more common method of storing interrupt context on a stack. The AT89S52UART an be configured to use a 9th data bit that can provide addressable communications in an RS-485 multi-point communications environment. AT89S52 based microcontrollers typically include one or two UARTs, two or three timers, 128 or 256 bytes of internal data RAM (16 bytes of which are bit addressable), up to 128 bytes of I/O, 512 bytes to 64 kB of internal program memory, and sometimes a quantity of extended data RAM(ERAM) located in the external data space. The original AT89S52 core ran at 12 clock cycles per machine cycle, with most instructions executing in one or two machine cycles. With a 12 MHz clock frequency, the AT89S52 could thus execute 1 million one-cycle instructions per second or 500,000 two-cycle instructions per second. Enhanced 8051 cores are now commonly used which run at six, four, two, or even one clock per machine cycle, and have clock frequencies of up to 100 MHz, and are thus capable of an even greater number of instructions per second. All SILabs, some Dallas and a few Atmel devices have single cycle cores. Even higher speed single cycle 8051 cores, in the range 130 MHz to 150 MHz, are now available in internet downloadable form for use in programmable logic devices such as FPGAs, and at many hundreds of MHz in ASICs, for example the net list from www.e8051.com. Common features included in modern 8051 based microcontrollers include built-in reset timers with brown-out detection, on-chip oscillators, self-programmable Flash ROM program memory, boot loader code in ROM, EEPROM non-volatile data storage, IÂÂ ²C, SPI, and USB host interfaces, PWM generators, analog comparators, A/D and D/A converters, RTCs, extra counters and timers, in-circuit debugging facilities, more interrupt sources, and extra power saving modes. Ref(3) PIN DIAGRAM:- Fig. 5 ref(3) Pins 1-8: Port 1 Each of these pins can be configured as input or output. Pin 9: RS Logical one on this pin stops microcontrollers operating and erases the contents of most registers. By applying logical zero to this pin, the program starts execution from the beginning. In other words, a positive voltage pulse on this pin resets the microcontroller. Pins10-17: Port 3 Similar to port 1, each of these pins can serve as universal input or output . Besides, all of them have alternative functions: Pin 10: RXD Serial asynchronous communication input or Serial synchronous communication output. Pin 11: TXD Serial asynchronous communication output or Serial synchronous communication clock output. Pin 12: INT0 Interrupt 0 input Pin 13: INT1 Interrupt 1 input Pin 14: T0 Counter 0 clock input Pin 15: T1 Counter 1 clock input Pin 16: WR Signal for writing to external (additional) RAM Pin 17: RD Signal for reading from external RAM Pin 18, 19: X2, X1 Internal oscillator input and output. A quartz crystal which determines operating frequency is usually connected to these pins. Instead of quartz crystal, the miniature ceramics resonators can be also used for frequency stabilization. Later versions of the microcontrollers operate at a frequency of 0 Hz up to over 50 Hz. Pin 20: GND Ground Pin 21-28: Port 2 If there is no intention to use external memory then these port pins are configured as universal inputs/outputs. In case external memory is used then the higher address byte, i.e. addresses A8-A15 will appear on this port. It is important to know that even memory with capacity of 64Kb is not used ( i.e. note all bits on port are used for memory addressing) the rest of bits are not available as inputs or outputs. Pin 29: PSEN If external ROM is used for storing program then it has a logic-0 value every time the microcontroller reads a byte from memory. Pin 30: ALE Prior to each reading from external memory, the microcontroller will set the lower address byte (A0-A7) on P0 and immediately after that activates the output ALE. Upon receiving signal from the ALE pin, the external register (74HCT373 or 74HCT375 circuit is usually embedded ) memorizes the state of P0 and uses it as an address for memory chip. In the second part of the microcontrollers machine cycle, a signal on this pin stops being emitted and P0 is used now for data transmission (Data Bus). In this way, by means of only one additional (and cheap) integrated circuit, data multiplexing from the port is performed. This port at the same time used for data and address transmission. Pin 31: EA By applying logic zero to this pin, P2 and P3 are used for data and address transmission with no regard to whether there is internal memory or not. That means that even there is a program written to the microcontroller, it will not be executed, the program written to external ROM will be used instead. Otherwise, by applying logic one to the EA pin, the microcontroller will use both memories, first internal and afterwards external (if it exists), up to end of address space. Pin 32-39: Port 0 Similar to port 2, if external memory is not used, these pins can be used as universal inputs or outputs. Otherwise, P0 is configured as address output (A0-A7) when the ALE pin is at high level (1) and as data output (Data Bus), when logic zero (0) is applied to the ALE pin. Pin 40: VCC Power supply +5V Ref(4) REGULATOR(7805):- 7805 is an integrated three-terminal positive fixed linear voltage regulator. It supports an input voltage of 7 volts to 35 volts and output voltage of 5 volts. It typically has a current rating of 1 amp although both higher and lower current models are available. Its output voltage is fixed at 5.0V. The 7805 also have a built-in current limiter as a safety feature. The 7805 will automatically reduce output current if it gets too hot. It belongs to a family of three-terminal positive fixed regulators with similar specifications and differing fixed voltages from 8 to 15 volts. The last two digits represent the voltage; for instance, the 7812 is a 12-volt regulator. The 78xx series of regulators is designed to work in complement with the 79xx series of negative voltage regulators in systems that provide both positive and negative regulated voltages, since the 78xx series cant regulate negative voltages in such a system. The 7805 is one of the most common and well known of the 78xx series regulators, as its small component count and medium-power regulated 5V make it useful for powering TTL. Fig.6 Ref(5) REFERENCES Search Enginewww.google.com. Data Sheets from www.alldatasheet.com Article on Password Based Security System on www.8051projectinfo.com Data Sheet of Microcontroller from www.atmel .com Article on Password based security system from Wikipedia. Text Book on 8051 Microcontroller (Mazidi) Text book on 8051 Microcontroller(Kenneth J. Ayala)