Introduction to Logic Gates Logical gates Inverter AND OR NAND NOR Exclusive OR (XOR) Exclusive NOR (XNOR) Draw Logic Circuit Analysis of Logic Circuit MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Introduction to Logic Gates Universal gates NAND and NOR NAND gate NOR gate Execution using NAND gate Execution using NOR gate Positive & Negative Logic SOP Expression Execution POS Expression Execution Integrated Logic Circuit Family MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Logic Gates MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Logic Gates Inverter gate The use of inverter: complement MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Logic Gates AND gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Logic Gates OR gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Logic Gates NAND gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Logic Gates NOR gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Logic Gates Exclusive OR (XOR) gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Logic Gates Exclusive NOR (XNOR) gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Draw Logic Gates When Boolean expression is obtained, we can draw logic gates Example: F1 = xyz’ (use three input AND gate) MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Draw Logic Gates MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Logic Circuit Analysis When logic circuit is given, we can analyze the circuit to obtain logical expression Example: What is the Boolean expression for F4 MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Logic Circuit Analysis What is the Boolean expression for F5 MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Universal Gates: NAND & NOR Gate AND/OR/NOT is enough to build any Boolean function Even though, other gates is also used because: Very useful (no choice) Save transistor’s number Self sufficient (can build any gate from it) NAND/NOR: save, self sufficient XOR: useful (e.g. execute parity bit) MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR NAND Gate NAND gate is self sufficient (i.e.can build any gate from it) Can be used for building AND/OR/NOT gate Build NOT gate using NAND gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR NAND Gate Build AND gate using NAND gates Build OR gate using NAND gates MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR NOR Gate NOR gate is also self sufficient Can be used for building AND/OR/NOT gate Build NOT gate using NOR gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR NOR Gate Build AND gate using NOR gates Build OR gate using NOR gates MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Build using NAND gate It is not impossible to build Boolean expression using NAND gates Steps Obtain sum-of-product Boolean expression E.g: F3 = xy’ +x’z Use DeMorgan theorem to get expression using two level NAND gate = (xy’+x’z)” = ((xy’)’.(x’z)’)’ MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Build using NAND gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Build using NOR gate It is not impossible to build Boolean expression using NOR gates Steps Obtain product-of-sum Boolean expression E.g: F6 = (x+y’).(x’+z) Use DeMorgan theorem to get expression using two level NAND gate E.g: F3 = (x+y’).(x’+z) =((x+y’).(x’+z))’’ = ((x+y’)+(x’+z)’)’ MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR Build using NOR gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Positive & Negative Logic In logic gate, most of the time H (High Voltage, 5V) = logic 1 L (Low Voltage, 0V) = logic 0 This is called positive logic However, if it is inverted, it is negative logic H (High Voltage, 5V) = logic 0 L (Low Voltage, 0V) = logic 1 Depends, some similar gate need different Boolean function MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Positive & Negative Logic Signal which is set to logic 1 is said to be active and true Signal which is set to logic 0 is said to be not active and false The name of active high signal is always written in non-compliment form The name of active low signal is always written in non-compliment form MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Positive & Negative Logic MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Construction of SOP Expression Sum-of-product expression can be built using Two level logic gate AND-OR Two level logic gate AND-NOT Logic AND-OR gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Construction of SOP Expression NAND-NAND circuit (with transformation circuit) Add two balls Change OR with NAND with inverted input and ball on it’s compliment input MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Construction of POS Expression Product-of-sum expression can be built using Two level logic gate AND-OR Two level logic gate AND-NOT Logic AND-OR gate MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR

Construction of POS Expression NOR-NOR circuit (with transformation circuit) Add two balls Change AND with NOR with inverted input and ball on it’s compliment input   ”: MOHD. YAMANI IDRIS/ NOORZAILY MOHAMED NOOR