Chapter4GatesandCircuits1
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High voltage High voltage
Low voltage
No volt falling! Low voltage
No current! Insulator!
Current through, no resistence, conductor!
Chapter 4 Gates and Circuits
Chapter 4 Gates and Circuits
Key Terms
Two circuits are equivalent if and only if they perform the same function(功能,函数)
circuit equivalence(等值电路):
Boolean algebra, logic diagram, truth table: 布尔代数， 逻辑图， 真值表
Review of Gate Processing
An XOR gate produces 1 if one or the other (but not both) input values are 1 A NAND gate produces the opposite results of an AND gate A NOR gate produces the opposite results of an OR gate
OR Gate
If the two input values are both 0, the output value is 0; otherwise, the output is 1
Figure 4.3 Various representations of a OR gate
XOR Gate
Chapter 4 Gates and Circuits
Key Terms
circuit: combinational circuit(组合电路) adder, full adder, half adder 加法器, 全加器, 半加器 multiplexer(多路选择器) sequential circuit(时序电路)
AND Gate
An AND gate accepts two input signals If the two input values for an AND gate are both 1, the output is 1; otherwise, the output is 0
Figure 4.2 Various representations of an AND gate
Summary of a transistor
A transistor can be either a conductor or an insulator, according to the voltage of the base. A transistor can be said to be a switch(开关) which is on or off, to let the current go through or block the current.
Chapter 4 Gates and Circuits
What’a a gate?
A gate is a transistor or a group of transistors connected to each other which performs a basic function(函数,功能). A function is a mapping(映射) between one or several inputs and one or several outputs. A function can be defined as a
Figure 4.7 Various representations of a three-input AND gate
Constructing Gates
A gate is made of one or several transistors Because the way a transistor works, the easiest gates to create are the NOT, NAND, and NOR gates
Chapter 4 Gates and Circuits
Summary of a transistor
A transistor has one of two states at any time: base=0 and source=1 base=1 and source=0 A transistor switches(切换) between these two states according to the base.
Chapter 4 Gates and Circuits
Question:
Any current(电流) from source to emitter?
Figure 4.8 The connection of a transistor
Chapter 4 Gates and Circuits
Two states of a transistor
The connection of a transistor
A source: connected to a high voltage A base: electrical pulse, high or low voltage An emitter: a low voltage
Figure 4.8 The connection of a transistor
Figure 4.5 Various representations of a NAND gate
Figure 4.6 Various representations of a NOR gate
4–15
Review of Gate Processing
A NOT gate inverts its single input value An AND gate produces 1 if both input values are 1 An OR gate produces 1 if one or the other or both input values are 1
Chapter 4 Gates and Circuits
What’s a circuit?
A circuit is a gate or a group of gates connected to each other which performs a pretty complex, important task. A task that performed by a circuit is often one basic operation which happens when a computer executes an instruction(指令). For example, add two bits together, store a bit.
XOR Gate
Figure 4.4 Various representations of an XOR gate
NAND and NOR Gates
The NAND and NOR gates are essentially the opposite of the AND and OR gates, respectively
Chapter 4 Gates and Circuits
Key Tercircuit(电路，门电路) integrated circuit(集成电路)/chip(芯片) semiconductor(半导体) conductor(导体) insulator(绝缘体)
A transistor made of a semiconductor material
neither a good conductor of electricity, such as copper, nor a good insulator, such as rubber
Figure Logical diagram of a transistor
Boolean expression truth table logic diagram
Chapter 4 Gates and Circuits
Gates categories
6 important kinds of gates
NOT 非门 AND 与门 OR 或门 XOR 异或门 NAND 与非门 NOR 或非门 Please remember 3 representations of every gate.
Gates with More Inputs
Gates can be designed to accept three or more input values A three-input AND gate, for example, produces an output of 1 only if all input values are 1
XOR, or exclusive OR, gate
An XOR gate produces 0 if its two inputs are the same, and a 1 otherwise Note the difference between the XOR gate and the OR gate; they differ only in one input situation When both input signals are 1, the OR gate produces a 1 and the XOR produces a 0
Chapter 4 Gates and Circuits
A transistor has three terminals
A source (源极) A base (基极) An emitter (发射极)
Figure Logical diagram of a transistor
Chapter 4 Gates and Circuits
NOT Gate
A NOT gate accepts one input value and produces one output value
Figure 4.1 Various representations of a NOT gate
NOT Gate
By definition, if the input value for a NOT gate is 0, the output value is 1, and if the input value is 1, the output is 0 A NOT gate is sometimes referred to as an inverter because it inverts the input value
Chapter 4 Gates and Circuits
What is this chapter about?
the most fundamental/basic hardware elements of a computer computer science intersects electrical engineering
three methods to define/specify a circuit,which can be a gate
Chapter 4 Gates and Circuits
Transistors
Gates
Circuits
Integrated Circuits
Chapter 4 Gates and Circuits
Low voltage
No volt falling! Low voltage
No current! Insulator!
Current through, no resistence, conductor!
Chapter 4 Gates and Circuits
Chapter 4 Gates and Circuits
Key Terms
Two circuits are equivalent if and only if they perform the same function(功能,函数)
circuit equivalence(等值电路):
Boolean algebra, logic diagram, truth table: 布尔代数， 逻辑图， 真值表
Review of Gate Processing
An XOR gate produces 1 if one or the other (but not both) input values are 1 A NAND gate produces the opposite results of an AND gate A NOR gate produces the opposite results of an OR gate
OR Gate
If the two input values are both 0, the output value is 0; otherwise, the output is 1
Figure 4.3 Various representations of a OR gate
XOR Gate
Chapter 4 Gates and Circuits
Key Terms
circuit: combinational circuit(组合电路) adder, full adder, half adder 加法器, 全加器, 半加器 multiplexer(多路选择器) sequential circuit(时序电路)
AND Gate
An AND gate accepts two input signals If the two input values for an AND gate are both 1, the output is 1; otherwise, the output is 0
Figure 4.2 Various representations of an AND gate
Summary of a transistor
A transistor can be either a conductor or an insulator, according to the voltage of the base. A transistor can be said to be a switch(开关) which is on or off, to let the current go through or block the current.
Chapter 4 Gates and Circuits
What’a a gate?
A gate is a transistor or a group of transistors connected to each other which performs a basic function(函数,功能). A function is a mapping(映射) between one or several inputs and one or several outputs. A function can be defined as a
Figure 4.7 Various representations of a three-input AND gate
Constructing Gates
A gate is made of one or several transistors Because the way a transistor works, the easiest gates to create are the NOT, NAND, and NOR gates
Chapter 4 Gates and Circuits
Summary of a transistor
A transistor has one of two states at any time: base=0 and source=1 base=1 and source=0 A transistor switches(切换) between these two states according to the base.
Chapter 4 Gates and Circuits
Question:
Any current(电流) from source to emitter?
Figure 4.8 The connection of a transistor
Chapter 4 Gates and Circuits
Two states of a transistor
The connection of a transistor
A source: connected to a high voltage A base: electrical pulse, high or low voltage An emitter: a low voltage
Figure 4.8 The connection of a transistor
Figure 4.5 Various representations of a NAND gate
Figure 4.6 Various representations of a NOR gate
4–15
Review of Gate Processing
A NOT gate inverts its single input value An AND gate produces 1 if both input values are 1 An OR gate produces 1 if one or the other or both input values are 1
Chapter 4 Gates and Circuits
What’s a circuit?
A circuit is a gate or a group of gates connected to each other which performs a pretty complex, important task. A task that performed by a circuit is often one basic operation which happens when a computer executes an instruction(指令). For example, add two bits together, store a bit.
XOR Gate
Figure 4.4 Various representations of an XOR gate
NAND and NOR Gates
The NAND and NOR gates are essentially the opposite of the AND and OR gates, respectively
Chapter 4 Gates and Circuits
Key Tercircuit(电路，门电路) integrated circuit(集成电路)/chip(芯片) semiconductor(半导体) conductor(导体) insulator(绝缘体)
A transistor made of a semiconductor material
neither a good conductor of electricity, such as copper, nor a good insulator, such as rubber
Figure Logical diagram of a transistor
Boolean expression truth table logic diagram
Chapter 4 Gates and Circuits
Gates categories
6 important kinds of gates
NOT 非门 AND 与门 OR 或门 XOR 异或门 NAND 与非门 NOR 或非门 Please remember 3 representations of every gate.
Gates with More Inputs
Gates can be designed to accept three or more input values A three-input AND gate, for example, produces an output of 1 only if all input values are 1
XOR, or exclusive OR, gate
An XOR gate produces 0 if its two inputs are the same, and a 1 otherwise Note the difference between the XOR gate and the OR gate; they differ only in one input situation When both input signals are 1, the OR gate produces a 1 and the XOR produces a 0
Chapter 4 Gates and Circuits
A transistor has three terminals
A source (源极) A base (基极) An emitter (发射极)
Figure Logical diagram of a transistor
Chapter 4 Gates and Circuits
NOT Gate
A NOT gate accepts one input value and produces one output value
Figure 4.1 Various representations of a NOT gate
NOT Gate
By definition, if the input value for a NOT gate is 0, the output value is 1, and if the input value is 1, the output is 0 A NOT gate is sometimes referred to as an inverter because it inverts the input value
Chapter 4 Gates and Circuits
What is this chapter about?
the most fundamental/basic hardware elements of a computer computer science intersects electrical engineering
three methods to define/specify a circuit,which can be a gate
Chapter 4 Gates and Circuits
Transistors
Gates
Circuits
Integrated Circuits
Chapter 4 Gates and Circuits