How computers work Part 1 Combinational Logic What

How computers work? (Part 1 - Combinational Logic) What is a Logic Gate? Ravi Raizada Limrose Group, Wrexham, UK

limrose Computer are many things to people! Keyboards, Screens, Disk Drives, Robots, Internet?

limrose The computer is NOT only keyboards and LCD Screens. Computers are NOT just a box of complex electronics. Computer is NOT even a clever Robot. And. NOT a jumble of Zeros and Ones. What is it then?

Hardware: electro-mechanical switches? limrose Not used in computers A Computer is: 1101 1011 0000 0777 1101 0011 0000 1100 0011 0000 DB 07 D 3 08 C 3 00 Millions of very fast, highly organised, electronic switches, controlled by billions of Zeros and Ones! Software – billions of organised zeros and Ones

limrose This is the symbol for an electronic switch, called a Transistor Several transistors connected together make a LOGIC GATE. Logic Gates

limrose Tutorkit Logic Tutor LT 1 A Tutorkit LT 1 A Logic Tutor has a collection of electronic Logic Gates to experiment, learn and understand how strange things like Half and Full Adders, Flip-flops and Code converters work?

limrose Logic Tutor LT 1 Front Panel Connections between logic gates are made using 1 mm Solderless Patch Leads

limrose Logic Gates can have several inputs, but usually one Output. Gate Outputs are either “ON” or “OFF” ON state is called 1 OFF state is called 0 Output of AND gate is logic 1 if both inputs A and B are at Logic 1 This is a AND gate

Truth Tables show the Output Q changes as Inputs A and B change limrose

limrose Testing the AND Gate Use 1 mm Solderless Patch Leads to connect as shown above

limrose Ex-OR Gate as a Controlled Switch Use 1 mm Solderless Patch Leads to connect as shown above

limrose 2 -bit Logic Comparator Use 1 mm Solderless Patch Leads to connect as shown above

limrose Half Adder – Sum and Carry Using 1 mm Solderless Patch Leads

limrose Memory using NAND Gate Latch Use 1 mm Solderless Patch Leads to connect as shown above

limrose And. more R-S and J_K Flip flops Code Generators Man, Sheep, Wolf, Cabbage puzzle 3 -Hats Problem Computer circuits Logical puzzles………. . .

limrose For advanced users: Sequential Logic Tutor LT 2 For Counters, Shift Registers, Chain Code Generator etc. Outputs depend on present Inputs and previous history. Karnaugh Map Tutor KMD 1 Map complex logic circuits, Use Boolean Algebra. Simplify and verify Boolean Logic etc.

limrose IC Patchboards to learn the “how” of Digital and Linear Integrated Circuits Robust, Low-cost, Reliable. Solderless Breaboard Plug- in your own Digital and Analog integrated circuits to make complex, real-life, computer circuits. Thousands in daily use in Schools, FE Colleges and Universities.

limrose Karnaugh Map Tutor The Karnaugh Map Tutor simplifies Boolean Logic for you to understand master this most interesting subject.

limrose Reliability of interconnections is most important. It is everything Low-cost, Robust, reliable

Customers include: limrose UK Ministry of Defence (Royal Navy, Royal Air Force) British Telecom Training and R&D Post Office college of Engineering Universities of Hull, York, Bradford etc. London and Metropolitan University Many UK FE and overseas colleges Colleges in Nigeria, Libya, Egypt, Saudi Arabia, Bahrain Hundred of UK schools Industrial Training organisations in UK and overseas Museum of Computing (Milton Keynes)

Limrose have helped thousands of teachers and college lecturers to learn, manipulate and exploit the mystery of zeros and ones Limrose Group (UK) Limited Tel: (44) 1978 85 5555 www. limrosegroup. com Copyright 2015 Limrose Group (UK)

limrose Limrose also designed and marketed the first Microprocessor Trainer in UK. Vintage Limrose logic training systems and computers are now housed in Museum of Computing in Milton Keynes (UK), where they are also used to introduce school children to the intellectually stimulating and fascinating subject of logic.

Thank you