Unit7 Digital Logic Circuit
2020/4/10
《电子技术专业英语教程》
1
Lesson 20 Flip-Flop
• Backgrounds • Text tour • Language in use
– Vocabulary – Structure – Reading/writing techniques
• The more advanced clocked devices are specially designed for synchronous systems; such devices therefore ignore its inputs except at the transition of a dedicated clock signal.
• This original electronic flip-flop——a simple two-input bistable circuit without any dedicated clock signal was transparent, and thus a device that would be labeled as a "latch" in many circles today.
• The name flip-flop was later derived from the sound produced on a speaker connected to one of the back coupled amplifiers outputs during the trigger process within the circuit.
2020/4/10
《电子技术专业英语教程》
4
Flip-flop
• In digital circuits, a flip-flop is a term referring to an electronic circuit (a bistable multivibrator) that has two stable states and thereby is capable of serving as one bit of memory.
2020/4/10《电子技术业英语教程》5Flip-flop’s invention
• The first electronic flip-flop was invented in 1918 by William Eccles and F. W. Jordan.
• It was initially called the Eccles-Jordan trigger circuit and consisted of two active elements.
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Text tour
• Outline
– Flip-flop – Flip-flop’s invention – Simple flip-flops – Clocked flip-flops – The type of flip-flops
• Set–reset flip-flops (SR flip-flops) • Trigger flip-flops (T flip-flops) • JK flip-flop • D flip-flop
• Today, the term flip-flop has come to mostly denote nontransparent (clocked or edge-triggered) devices, while the simpler transparent ones are often referred to as latches; however, as this distinction is quite new, the two words are sometimes used interchangeably.
• A flip-flop is usually controlled by one or two control signals and/or a gate or clock signal. The output often includes the complement as well as the normal output. As flip-flops are implemented electronically, they require power and ground connections.
• This causes the flip-flop to either change or retain its output signal based upon the values of the input signals at the transition.
2020/4/10
《电子技术专业英语教程》
2
Backgrounds
• Terminology
– multivibrator
• n.【计】多谐振荡器
– field effect transistor
• 【计】场效应晶体管
– shift register
• 移位寄存器
2020/4/10
《电子技术专业英语教程》
2020/4/10
《电子技术专业英语教程》
6
Simple flip-flops
• Simple flip-flops can be built around a pair of cross-coupled inverting elements: vacuum tubes, bipolar transistors, field effect transistors, inverters, and inverting logic gates have all been used in practical circuits-perhaps augmented by some gating mechanism .