or
Subelement L06
Basic Digital Techniques.
Section L06
What is a NAND gate?
• A circuit that produces a logic "1" at its output only when all inputs are logic "1"
• A circuit that produces a logic "0" at its output if some but not all of its inputs are logic "1"
• A circuit that produces a logic "0" at its output only when all inputs are logic "0"
A circuit that produces a logic "0" at its output only when all inputs are logic "1"

Logic circuitry uses three main operations: "AND", "OR" and "NOT". The "NOT" is also called negation, complement or inversion. AND: true if both inputs are true. NAND: AND followed by a NOT, false when both inputs are true (AND, NAND: all inputs have a desired state). OR: true if either input is true. NOR: OR followed by a NOT, false if either input is true (OR,NOR: at least one input has desired state). XOR: true if both inputs are complementary. XNOR: XOR followed by a NOT, false if both inputs are complementary (XOR,XNOR: only one input has a desired state).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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What is an OR gate?
• A circuit that produces logic "1" at its output if all inputs are logic "0"
• A circuit that produces a logic "0" at its output if any input is logic "1"
A circuit that produces a logic "1" at its output if any input is logic "1"
• A circuit that produces a logic "0" at its output if all inputs are logic "1"

Logic circuitry uses three main operations: "AND", "OR" and "NOT". The "NOT" is also called negation, complement or inversion. AND: true if both inputs are true. NAND: AND followed by a NOT, false when both inputs are true (AND, NAND: all inputs have a desired state). OR: true if either input is true. NOR: OR followed by a NOT, false if either input is true (OR,NOR: at least one input has desired state). XOR: true if both inputs are complementary. XNOR: XOR followed by a NOT, false if both inputs are complementary (XOR,XNOR: only one input has a desired state).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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What is a NOR gate?
• A circuit that produces a logic "1" at its output if some but not all of its inputs are logic "1"
A circuit that produces a logic "0" at its output if any or all inputs are logic "1"
• A circuit that produces a logic "0" at its output only if all inputs are logic "0"
• A circuit that produces a logic "1" at its output only if all inputs are logic "1"

Logic circuitry uses three main operations: "AND", "OR" and "NOT". The "NOT" is also called negation, complement or inversion. AND: true if both inputs are true. NAND: AND followed by a NOT, false when both inputs are true (AND, NAND: all inputs have a desired state). OR: true if either input is true. NOR: OR followed by a NOT, false if either input is true (OR,NOR: at least one input has desired state). XOR: true if both inputs are complementary. XNOR: XOR followed by a NOT, false if both inputs are complementary (XOR,XNOR: only one input has a desired state).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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What is a NOT gate (also known as an INVERTER)?
A circuit that produces a logic "0" at its output when the input is logic "1"
• A circuit that does not allow data transmission when its input is high
• A circuit that allows data transmission only when its input is high
• A circuit that produces a logic "1" at its output when the input is logic "1"

Logic circuitry uses three main operations: "AND", "OR" and "NOT". The "NOT" is also called negation, complement or inversion. AND: true if both inputs are true. NAND: AND followed by a NOT, false when both inputs are true (AND, NAND: all inputs have a desired state). OR: true if either input is true. NOR: OR followed by a NOT, false if either input is true (OR,NOR: at least one input has desired state). XOR: true if both inputs are complementary. XNOR: XOR followed by a NOT, false if both inputs are complementary (XOR,XNOR: only one input has a desired state).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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What is an EXCLUSIVE OR gate?
• A circuit that produces a logic "1" at its output when all of the inputs are logic "1"
• A circuit that produces a logic "1" at its output when all of the inputs are logic "0"
A circuit that produces a logic "1" at its output when only one of the inputs is logic "1"
• A circuit that produces a logic "0" at its output when only one of the inputs is logic "1"

Logic circuitry uses three main operations: "AND", "OR" and "NOT". The "NOT" is also called negation, complement or inversion. AND: true if both inputs are true. NAND: AND followed by a NOT, false when both inputs are true (AND, NAND: all inputs have a desired state). OR: true if either input is true. NOR: OR followed by a NOT, false if either input is true (OR,NOR: at least one input has desired state). XOR: true if both inputs are complementary. XNOR: XOR followed by a NOT, false if both inputs are complementary (XOR,XNOR: only one input has a desired state).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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What is an EXCLUSIVE NOR gate?
• A circuit that produces a logic "1" at its output when only one of the inputs is logic "0"
• A circuit that produces a logic "1" at its output when only one of the inputs are logic "1"
• A circuit that produces a logic "0" at its output when all of the inputs are logic "1"
A circuit that produces a logic "1" at its output when all of the inputs are logic "1"

Logic circuitry uses three main operations: "AND", "OR" and "NOT". The "NOT" is also called negation, complement or inversion. AND: true if both inputs are true. NAND: AND followed by a NOT, false when both inputs are true (AND, NAND: all inputs have a desired state). OR: true if either input is true. NOR: OR followed by a NOT, false if either input is true (OR,NOR: at least one input has desired state). XOR: true if both inputs are complementary. XNOR: XOR followed by a NOT, false if both inputs are complementary (XOR,XNOR: only one input has a desired state).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What is an AND gate?
• A circuit that produces a logic "1" at its output only if one of its inputs is logic "1"
• A circuit that produces a logic "1" at its output if all inputs are logic "0"
A circuit that produces a logic "1" at its output only if all its inputs are logic "1"
• A circuit that produces a logic "1" at the output if at least one input is a logic "0"

Logic circuitry uses three main operations: "AND", "OR" and "NOT". The "NOT" is also called negation, complement or inversion. AND: true if both inputs are true. NAND: AND followed by a NOT, false when both inputs are true (AND, NAND: all inputs have a desired state). OR: true if either input is true. NOR: OR followed by a NOT, false if either input is true (OR,NOR: at least one input has desired state). XOR: true if both inputs are complementary. XNOR: XOR followed by a NOT, false if both inputs are complementary (XOR,XNOR: only one input has a desired state).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What is a flip-flop circuit?
• A binary sequential logic element with one stable state
A binary sequential logic element with two stable states
• A binary sequential logic element with eight stable states
• A binary sequential logic element with four stable states

The "flip-flop" is a bistable multivibrator. The adjective "bistable" alludes to two possible stable states, set or reset. The circuit remains in one of the two states until a change is triggered. The terms "flip-flop" and "latch" are sometimes used interchangeably. Simple logic gates implement Combinational Logic: the output is determined only by the current inputs. In Sequential Logic, the output depends on current inputs and the exact sequence of prior events. [ Nowadays, purists will tell you that a latch follows the input levels (transparency) before a final value is locked-in; a flip-flop captures data strictly on a clock transition (edge-triggered). ]

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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What is a bistable multivibrator?
A flip-flop
• An OR gate
• An AND gate
• A clock

The "flip-flop" is a bistable multivibrator. The adjective "bistable" alludes to two possible stable states, set or reset. The circuit remains in one of the two states until a change is triggered. The terms "flip-flop" and "latch" are sometimes used interchangeably. Simple logic gates implement Combinational Logic: the output is determined only by the current inputs. In Sequential Logic, the output depends on current inputs and the exact sequence of prior events. [ Nowadays, purists will tell you that a latch follows the input levels (transparency) before a final value is locked-in; a flip-flop captures data strictly on a clock transition (edge-triggered). ]

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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What type of digital logic is also known as a latch?
• A decade counter
• An OR gate
• An op-amp
A flip-flop

The "flip-flop" is a bistable multivibrator. The adjective "bistable" alludes to two possible stable states, set or reset. The circuit remains in one of the two states until a change is triggered. The terms "flip-flop" and "latch" are sometimes used interchangeably. Simple logic gates implement Combinational Logic: the output is determined only by the current inputs. In Sequential Logic, the output depends on current inputs and the exact sequence of prior events. [ Nowadays, purists will tell you that a latch follows the input levels (transparency) before a final value is locked-in; a flip-flop captures data strictly on a clock transition (edge-triggered). ]

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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In a multivibrator circuit, when one transistor conducts, the other is:
• saturated
• reverse-biased
• forward-biased