Thursday, 28 June 2012

Integrated Circuits (Chips)


Integrated Circuits (Chips)

Pin numbers | IC holders | Static | Datasheets | Sinking/sourcing | Combining outputs |
555 and 556 Timers | Logic ICs | 4000 Series | 74 Series | PIC microcontrollers

Also see: 4000 Series ICs | 74 Series ICs | 555 and 556 Timer Circuits

Integrated Circuits are usually called ICs or chips. They are complex circuits which have been etched onto tiny chips of semiconductor (silicon). The chip is packaged in a plastic holder with pins spaced on a 0.1" (2.54mm) grid which will fit the holes on stripboard and breadboards. Very fine wires inside the package link the chip to the pins.
IC pin numbers

Pin numbers

The pins are numbered anti-clockwise around the IC (chip) starting near the notch or dot. The diagram shows the numbering for 8-pin and 14-pin ICs, but the principle is the same for all sizes. 

IC holders (DIL sockets)

IC holder (DIL socket)ICs (chips) are easily damaged by heat when soldering and their short pins cannot be protected with a heat sink. Instead we use an IC holder, strictly called a DIL socket (DIL = Dual In-Line), which can be safely soldered onto the circuit board. The IC is pushed into the holder when all soldering is complete.IC holders are only needed when soldering so they are not used on breadboards.
Commercially produced circuit boards often have ICs soldered directly to the board without an IC holder, usually this is done by a machine which is able to work very quickly. Please don't attempt to do this yourself because you are likely to destroy the IC and it will be difficult to remove without damage by de-soldering.

Removing an IC from its holder

If you need to remove an IC it can be gently prised out of the holder with a small flat-blade screwdriver. Carefully lever up each end by inserting the screwdriver blade between the IC and its holder and gently twisting the screwdriver. Take care to start lifting at both ends before you attempt to remove the IC, otherwise you will bend and possibly break the pins. 

Static precautions

Antistatic bags for ICs
Antistatic bags for ICs
Photograph © Rapid Electronics
Many ICs are static sensitive and can be damaged when you touch them because your body may have become charged with static electricity, from your clothes for example. Static sensitive ICs will be supplied in antistatic packaging with a warning label and they should be left in this packaging until you are ready to use them.It is usually adequate to earth your hands by touching a metal water pipe or window frame before handling the IC but for the more sensitive (and expensive!) ICs special equipment is available, including earthed wrist straps and earthed work surfaces. You can make an earthed work surface with a sheet of aluminium kitchen foil and using a crocodile clip to connect the foil to a metal water pipe or window frame with a 10kohm resistor in series.

Datasheets

PDF files
To view and print PDF files you need an Acrobat Reader which may be downloaded free for WindowsMac,RISC OS, or UNIX/Linux computers. If you are not sure which type of computer you have it is probably Windows.
Datasheets are available for most ICs giving detailed information about their ratings and functions. In some cases example circuits are shown. The large amount of information with symbols and abbreviations can make datasheets seem overwhelming to a beginner, but they are worth reading as you become more confident because they contain a great deal of useful information for more experienced users designing and testing circuits.Datasheets are available as PDF files from:


sinking and sourcing current

Sinking and sourcing current

IC outputs are often said to 'sink' or 'source' current. The terms refer to the direction of the current at the IC's output.If the IC is sinking current it is flowing into the output. This means that a device connected between the positive supply (+Vs) and the IC output will be switched on when the output is low (0V).
If the IC is sourcing current it is flowing out of the output. This means that a device connected between the IC output and the negative supply (0V) will be switched on when the output is high (+Vs).
It is possible to connect two devices to an IC output so that one is on when the output is low and the other is on when the output is high. This arrangement is used in the Level Crossing project to make the red LEDs flash alternately.
The maximum sinking and sourcing currents for an IC output are usually the same but there are some exceptions, for example 74LS TTL logic ICs can sink up to 16mA but only source 2mA.

Using diodes to combine outputs

using diodes to combine outputsThe outputs of ICs must never be directly connected together. However, diodes can be used to combine two or more digital (high/low) outputs from an IC such as a counter. This can be a useful way of producing simple logic functions without using logic gates!The diagram shows two ways of combining outputs using diodes. The diodes must be capable of passing the output current. 1N4148 signal diodes are suitable for low current devices such as LEDs.
For example the outputs Q0 - Q9 of a 4017 1-of-10 counter go high in turn. Using diodes to combine the 2nd (Q1) and 4th (Q3) outputs as shown in the bottom diagram will make the LED flash twice followed by a longer gap. The diodes are performing the function of an OR gate.
Example projects: Traffic Light | Dice | Model Lighthouse

555 and 556 pins

The 555 and 556 Timers

The 8-pin 555 timer IC is used in many projects, a popular version is the NE555. Most circuits will just specify '555 timer IC' and the NE555 is suitable for these. The 555 output (pin 3) can sink and sourceup to 200mA. This is more than most ICs and it is sufficient to supply LEDs, relay coils and low current lamps. To switch larger currents you can connect a transistor.The 556 is a dual version of the 555 housed in a 14-pin package. The two timers (A and B) share the same power supply pins.
Low power versions of the 555 are made, such as the ICM7555, but these should only be used when specified (to increase battery life) because their maximum output current of about 20mA (with 9V supply) is too low for many standard 555 circuits. The ICM7555 has the same pin arrangement as a standard 555.
For further information please see the page on 555 and 556 timer circuits.

Logic ICs (chips)

Logic ICs process digital signals and there are many devices, including logic gates, flip-flops, shift registers, counters and display drivers. They can be split into two groups according to their pin arrangements: the 4000 series and the 74 series which consists of various families such as the 74HC, 74HCT and 74LS.For most new projects the 74HC family is the best choice. The older 4000 series is the only family which works with a supply voltage of more than 6V. The 74LS and 74HCT families require a 5V supply so they are not convenient for battery operation.
The table below summarises the important properties of the most popular logic families:

Property4000 Series74 Series
74HC
74 Series
74HCT
74 Series
74LS
TechnologyCMOSHigh-speed CMOSHigh-speed CMOS
TTL compatible
TTL Low-power Schottky
Power Supply3 to 15V2 to 6V5V ±0.5V5V ±0.25V
InputsVery high impedance. Unused inputs must be connected to +Vs or 0V. Inputs cannot be reliably driven by 74LS outputs unless a 'pull-up' resistor is used (see below).Very high impedance. Unused inputs must be connected to +Vs or 0V. Compatible with 74LS (TTL) outputs.'Float' high to logic 1 if unconnected. 1mA must be drawn out to hold them at logic 0.
OutputsCan sink and source about 5mA (10mA with 9V supply), enough to light an LED. To switch larger currents use atransistor.Can sink and source about 20mA, enough to light an LED. To switch larger currents use atransistor.Can sink and source about 20mA, enough to light an LED. To switch larger currents use a transistor.Can sink up to 16mA (enough to light an LED), but source only about 2mA. To switch larger currents use atransistor.
Fan-outOne output can drive up to 50 CMOS, 74HC or 74HCT inputs, but only one 74LS input.One output can drive up to 50 CMOS, 74HC or 74HCT inputs, but only 10 74LS inputs.One output can drive up to 10 74LS inputs or 50 74HCT inputs.
Maximum Frequencyabout 1MHzabout 25MHzabout 25MHzabout 35MHz
Power consumption
of the IC itself
A few µW.A few µW.A few µW.A few mW.


using a pull-up resistor
Driving 4000 or 74HC inputs from a
74LS output using a pull-up resistor.

Mixing Logic Families

It is best to build a circuit using just one logic family, but if necessary the different families may be mixed providing the power supply is suitable for all of them. For example mixing 4000 and 74HC requires the power supply to be in the range 3 to 6V. A circuit which includes 74LS or 74HCT ICs must have a 5V supply.A 74LS output cannot reliably drive a 4000 or 74HC input unless a 'pull-up' resistor of 2.2kohm is connected between the +5V supply and the input to correct the slightly different logic voltage ranges used.
Note that a 4000 series output can drive only one 74LS input.

Quick links to
individual ICs
4000    4060
4001    4068
4002    4069
4011    4070
4012    4071
4017    4072
4020    4073
4023    4075
4024    4077
4025    4081
4026    4082
4028    4093
4029    4510
4030    4511
4040    4516
4049    4518
4050    4520
 

4000 Series CMOS

This family of logic ICs is numbered from 4000 onwards, and from 4500 onwards. They have a B at the end of the number (e.g. 4001B) which refers to an improved design introduced some years ago. Most of them are in 14-pin or 16-pin packages. They use CMOS circuitry which means they use very little power and can tolerate a wide range of power supply voltages (3 to 15V) making them ideal for battery powered projects. CMOS is pronounced 'see-moss' and stands for Complementary Metal Oxide Semiconductor.However the CMOS circuitry also means that they are static sensitive. Touching a pin while charged with static electricity (from your clothes for example) may damage the IC. In fact most ICs in regular use are quite tolerant and earthing your hands by touching a metal water pipe or window frame before handling them will be adequate. ICs should be left in their protective packaging until you are ready to use them. For the more sensitive (and expensive!) ICs special equipment is available, including earthed wrist straps and earthed work surfaces.
For further information, including pin connections, please use the quick links on the right or go to 4000 Series ICs.

Quick links to
individual ICs7400    7432
7402    7442
7403    7447
7404    7486
7405    7490
7408    7493
7409  74132
7410  74160
7411  74161
7412  74162
7414  74163
7420  74192
7421  74193
7427  74390
7430  74393
74HC4017
74HC4020
74HC4040
74HC4060
74HC4511
 

74 Series: 74LS, 74HC and 74HCT

There are several families of logic ICs numbered from 74xx00 onwards with letters (xx) in the middle of the number to indicate the type of circuitry, eg 74LS00 and 74HC00. The original family (now obsolete) had no letters, eg 7400.The 74LS (Low-power Schottky) family (like the original) uses TTL (Transistor-Transistor Logic) circuitry which is fast but requires more power than later families.
The 74HC family has High-speed CMOS circuitry, combining the speed of TTL with the very low power consumption of the 4000 series. They are CMOS ICs with the same pin arrangements as the older 74LS family. Note that 74HC inputs cannot be reliably driven by 74LS outputs because the voltage ranges used for logic 0 are not quite compatible, use 74HCT instead.
The 74HCT family is a special version of 74HC with 74LS TTL-compatible inputs so 74HCT can be safely mixed with 74LS in the same system. In fact 74HCT can be used as low-power direct replacements for the older 74LS ICs in most circuits. The minor disadvantage of 74HCT is a lower immunity to noise, but this is unlikely to be a problem in most situations.
Beware that the 74 series is often still called the 'TTL series' even though the latest ICs do not use TTL!
For further information, including pin connections, please use the quick links on the right or go to 74 series ICs.
The CMOS circuitry used in the 74HC and 74HCT series ICs means that they are static sensitive. Touching a pin while charged with static electricity (from your clothes for example) may damage the IC. In fact most ICs in regular use are quite tolerant and earthing your hands by touching a metal water pipe or window frame before handling them will be adequate. ICs should be left in their protective packaging until you are ready to use them.

PIC microcontrollers

A PIC is a Programmable Integrated Circuit microcontroller, a 'computer-on-a-chip'. They have a processor and memory to run a program responding to inputs and controlling outputs, so they can easily achieve complex functions which would require several conventional ICs.
PICAXE
www.picaxe.co.uk
Programming a PIC microcontroller may seem daunting to a beginner but there are a number of systems designed to make this easy. The PICAXE system is an excellent example because it uses a standard computer to program (and re-program) the PICs; no specialist equipment is required other than a low-cost download lead. Programs can be written in a simple version of BASIC or using a flowchart. The PICAXE programming software and extensive documentation is available to download free of charge, making the system ideal for education and users at home. For further information (including downloads) please see www.picaxe.co.uk
If you think PICs are not for you because you have never written a computer program, please look at the PICAXE system! It is very easy to get started using a few simple BASIC commands and there are a number of projects available as kits which are ideal for beginners. The system is stocked by Rapid Electronics.

POWER TOOLS

PERSONAL, SOCIAL AND HEALTH EDUCATION WITH CITIZENSHIP



  

 
Personal, Social and Health Education is taught widely in UK schools, as well as Citizenship. Pupils are introduced to a range of topics and activities that help them develop as members of the community. Many of the activities below are aimed at helping pupils develop communication, discussion and reasoning skills
  
NOW WITH PRINTABLE WORKSHEETS (Still being upgraded)
  
 
ORGANISATION 
2. Are you Equipped to Learn?
3. Listening Skills
4. How to be Successful in Life
5. Organisation - Fire Drill Practice
6. Study and Revision Techniques
7. Revision Exercise
 
GROWING UP - ADOLESCENCE 
1. Growing Up - Adolescence 1 
2. Growing Up - Adolescence 2 
2. Growing Up - Adolescence 3 
PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEETS 
 
HELPING OTHERS
1. Helping Others / Putting Others First
2. Honesty
 
VANDALISM / ANTISOCIAL BEHAVIOUR
1. Vandalism - 1
2. The Cost of Vandalism
3. The Image of a Vandal
PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEET
4. Antisocial Behaviour
 
PRISON
1. Prison
2. Peer Pressure - Crime and Consequences
3. Peer Pressure, Antisocial behaviour and Prison
4. Life in Prison
5. Crime - More Consequences
 
BULLYING
1. Why Bullying is Wrong - 1
2. Why Bullying is Wrong - 2
3. Why Bullying is Wrong - 3
 
DOMESTIC ABUSE / VIOLENCE
1. Domestic Abuse / Violence - 1
2. Domestic Abuse /Violence - 2
PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEET
 
SCHOOL
1. New Pupil in School?
2. What Do You Know About Your School? (New Pupil in School)
3. What Do You Know About Your New School - Teachers and Subjects
4. Classroom Rules
5. A New School Year - Year 9
6. A New School Year - Year 10
7. A New school Year - Year 11
 
FRIENDSHIP
1. Friendship - 1
2. Friendship - 2
3. Friendship - 3
4. My Type of Friend
 
CITIZENSHIP
2. Why it is Important to be a Good Citizen
4.Citizenship and Crime
5. British Citizen Quiz - 1
6. British Citizen Quiz - 2
7. Good Citizen - Board Game Design
8. Citizenship Board Game Evaluation
9. School Report - Self Evaluation and Citizenship
10. Writing a Citizen Annual Report
12. Respect and other Cultures / Belief Systems
13. Helping Others - Putting Others First
 
HEALTH
2. Drink Responsibly - 1
3. Drink Responsibly - 2
4. Alcohol Abuse
5. Alcohol - The Facts - Newspaper Report
6. Alcohol - Scenarios
7. Teenage Health - 1
8. Teenage Health - 2 - Healthy Lifestyle Logo / Symbol Design
 
1. Road Safety - Motorcycles
2. Motor Cycle Safety - Poster Design
3. Driving Safely
 
THE INTERNET
1. The Internet - Uses and Dangers
 
ENVIRONMENT
1. Recycling
 
POLITICS
1. What is a General Election?
2. What is a Political Party?
  
LOOKING AHEAD
4. Year 9 - Options
  
CHARITY
2. A Difficult Customer?
3. Voluntary Groups
 
ACCOMODATION
1. The Homeless - 1
2. Homeless - Basic Worksheet with Prompts
4. Sharing Living Accommodation - 1
5. Sharing Living Accommodation - 2
6. Poverty and Slums
 
 
FINANCE
1. Money
2. Money and Wealth
3. The True Cost of Our Luxuries
4. Banks
 
THE DISABLED AND DISABILITIES
1. The Disabled, Disabilities and Athletes
2. The Disabled - Preventable Brain Injuries
 
 
 

DIPLOMA AND VOCATIONAL WORK



V. Ryan © 2002 - 2009
(STILL UNDER CONSTRUCTION)
Diplomas and Vocational work provide pupils and students with a way of learning that is based the study of business and industry. Furthermore, it allows pupils/students to study in a business and industrial context. Below are diploma/vocational projects whereby pupils build a portfolio of work based on their own research and investigation, linked closely to business and industry methodology. This section has close links with the design process sectionequipment and processesgearsmechanismsmicrocontroller andelectronics sections of this site so it is advisable to use both together.
 
  
 
THE CD-ROM STORAGE PROBLEM
COMPANY ORGANISATION
SCALES OF PRODUCTION
This unit takes pupils through the stages involved in the design of a storage unit and involves working as part of a team
 
This unit looks at the way departments are organised and the way they function within a company. The work roles of people in departments are investigated. All work in the classroom should be linked to a visit to a company.
 
In this unit pupils will study 'scales of production', including single item, batch and continuous production.
Industrial visits or video examples of each scale are essential for this section of the course
1. Setting the Scene 1. Organisational Structure 1. Scales of Production ?
2. Key Needs (1) 2. Company Work Roles 2. Continuous Production
3. Key Needs(2) 3. Departmental Functions 3. Batch Production
4. Design Brief 4. Work Role Responsibilities 4. Single Item Production
5. Client Needs 5. Interaction of Departments 5. Examples - Continuous Prod.
6. Product Constraints6. Examples - Batch Prod.
7. Functional Details
QUALITY ASSURANCE
7. Examples - Single Item
8. Basic Designs 
In this small project pupils put together a report on quality assurance with regards to the manufacture of the CD-ROM storage unit.
 8. Single Item -
9. Design Team Meeting  Materials/Components
10. Presentation to the Group  9. Single Item - Sequence drawing
11. Design Requirements  10. Single Item - Health and
12. Ideas and FeaturesSafety
13. Stages of Production 1. Introduction 11. Batch Prod. Conditions in the
14. The Specification2. Quality ChecksWorkplace
15. Team Discussion 3. Identifying Defects 12. Continuous Prod. Conditions
16. Selected Solution 4. Defective Products in the Workplace
17. Sequence Drawing 5. Industrial Quality Checks 13. Continuous Prod -
18. Product Feasibility   Materials/Components
19. Proposal Feasibility   14. Continuous Prod- Sequence
20. Planning for Mass Production   Drawing
21. Quality Control   15. Continuous Prod - Health and
    Safety
    16. The Report
    17. Quality Control
    18. Quality Control - Block
     Diagram
     
SCALES OF PRODUCTION - CASE STUDIES
When designing a product you will have to decide how it will be manufactured (made) in industry. Your final design could be manufactured by continuous production, batch production or single item production Your choice will depend on a number of factors, the most important being the customer or number of customers. Below is a simple Case Study of each scale of production. When you are working on a project you will need to explain how your design could be manufactured through each scale.
     
   
The manufacture of an individually designed and hand-made guitar.
The manufacture of a (batch) - large number of bicycles
The continuous manufacture - production 24 hours a day - of car bodies.
     
 INDUSTRIAL PRODUCTION 
   
 1. The Client /Customer 
 2. Introduction to Industrial Production Techniques 
 3. Scales of Production - an Introduction 
 4. Single Item / Prototype Production - Example 1 
 5. Single Item / Prototype Production - Example 2 
 6. Batch Production - Example 1 
 7. Batch Production - Example 2 
 8. Batch Production Exercise 
 9. Continuous Production - Example 1 
 10. Continuous Production - Example 2 
 11. Production Methods - Lesson Starter 
 12. CIM - Computer Integrated Manufacture - 1 
 13. CIM - Computer Integrated Manufacture - 2 
 14. Remote Manufacturing 
 15. Continuous Improvement (CI) - Page 1 
 16. Continuous Improvement (CI) - Page 2 
 17. Flexible Manufacturing Systems - FMS - 1 
 18. Flexible Manufacturing Systems - FMS - 2 
 19. Detailed Example of Flexible Manufacturing - CD / DVD Manufacture 
   
 20. Keeping a Manufacturing Logbook 
  

TECHNOLOGY AND ENVIRONMENT



 
V. Ryan © 2002 - 2009
 
Our society and industry relies on large amounts of energy and the world is becoming increasingly dependent on fossil fuels (oil, gas, coal etc...). The industrialised nations of Western Europe and North America, China and India depend almost entirely on these fuels and the developing nations are also increasing their use.
It is understood that there is a direct link between the way we produce energy and damage caused by pollution. Finding cleaner and alternative ways of producing electricity / energy are now looked upon as being very important for the future of our planet.

ALTERNATIVE ENERGY SOURCES
 
Alternative Energy is a term used to describe sources of energy that occur naturally in the environment. For example, energy from the sun, the wind, movement of the oceans, etc.... Click on aspects in the index below to view examples.
 
SOLAR POWER
 
 
 
 
WIND POWER
 
PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEET
 
 
PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEET - GENERAL QUESTIONS ON WIND POWER
 
 
SEA / TIDAL POWER
 
 
WAVE POWER
 
PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEET ON WAVE POWER
 
  
 
DAMS / HYDRO ELECTRICITY
 
 
 
DRINKING WATER
 
 
RAINWATER COLLECTION AND RECYCLING - PROJECT
 
 
GEOTHERMAL ENERGY
 
PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEET
 
MORE ALTERNATIVE ENERGY
 
 
 
NUCLEAR POWER GENERATION
 
 
CARBON FOOTPRINT
 
 
ENERGY SAVING DEVICES
 
 
LESSON MATERIAL
 
 
THE ENVIRONMENTALLY FRIENDLY HOUSE
 
 
 
ENVIRONMENTALLY TRANSPORT OF THE FUTURE
 

STRUCTURES AND THE ENVIRONMENT
  
  
DESIGN AND THE ENVIRONMENT