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1. Gymnastics a backward handspring
2. Electronics an electronic device or circuit that can assume either of two stable states by the application of a suitable pulse
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a trigger circuit (seeFLIP-FLOP CIRCUIT) that can remain for an arbitrary length of time in one of two (or, less frequently, of more than two) stable states and can be abruptly switched from one state to the other by the application of an input signal.

A flip-flop has two outputs: a main output and an inverse output. Specific output signals of differing levels correspond to each flip-flop state. In one state a high-level signal is formed at the main output, and a low-level signal is formed at the inverse output. In the other state the high-level and low-level signals are formed at the inverse and main outputs, respectively.

A flip-flop is characterized by the following important parameters: the speed, the response time, and the levels of the input and output signals. The speed is defined as the maximum possible number of switching operations per unit time. The response time is defined as the time required for the flip-flop to go from one state to the other; this time characterizes the time lag between the output signal and the input signal. The level of the input signal is understood to be the minimum signal value required to switch the flip-flop. The level of the output signal in most flip-flops is not lower than the level of the input signal; this situation makes it possible to connect flip-flops in series without intermediate amplification.

The most widely used types of flip-flops are electronic devices that incorporate such components as electron tubes, gas discharge devices, semiconductor diodes, various types of transistors, and, especially, integrated microcircuits. Flip-flops based on magnetic elements, pneumatic or hydraulic control devices, and other elements are also sometimes used. According to the nature of the input signals, flip-flops with potential inputs (direct and inverse) and with dynamic inputs (also direct and inverse) are distinguished. Flip-flops with potential inputs respond to a high-level signal at the direct input and a low-level signal at the inverse input. Flip-flops with dynamic inputs respond to differences between input signals, that is, to variations in signal levels. Such flip-flops respond to a positive difference at the direct input and to a negative difference at the inverse input.

A description of the most frequently used types of flip-flops follows. Flip-flops with a counting input (T flip-flops) change their state with each input signal. Flip-flops with two conditioning inputs (R-S flip-flops) change their state only when a control signal is applied to a specific input (the R or the S input); in this scheme the repeated action of a signal at the same input does not change the state of the flip-flop. Universal flip-flops (JK flip-flops) combine the properties of the T flip-flop and the R-S flip-flop. In delay flip-flops (D flip-flops) the state and the output signal corresponding to that state duplicate the input signal. In addition to flip-flops of these types there are also combination flip-flops, which are universal multifunction devices with large numbers of inputs.

The flip-flops described above are called symmetrical; asymmetrical flip-flops, or Schmitt triggers, are also used. An asymmetrical flip-flop goes from one state to the other when the input signal reaches a level called the response threshold and returns to the original state when the input signal decreases to a certain level. There are also multistable flip-flops, which have more than two stable states.

Flip-flops of various types are used in digital computers and in automation. With the use of flip-flops, one can construct such devices as digital automatic machines with program control for discrete data processing (for example, counters, scalers, registers of various kinds, decoders, and adders), pulse shapers, and digital frequency dividers. In digital automation flip-flops function as elementary automatic devices with a memory and two states corresponding to the two possible values of the binary logic variable (x = 0 and x = 1). Such flip-flops are classified as asynchronous or synchronous. Synchronous, or clocked, flip-flops operate only when periodic clock signals, usually of the meander type, that synchronize the operation of the flip-flop are applied to the inputs. Synchronous flip-flops are subdivided into single-cycle and double-cycle types. The latter type is a system consisting of two flip-flops that execute the same logic operation, but with a time shift equal to the duration of half a cycle of the input clock signal. This duplication of flip-flop operation is required for time division of the reception of the data conveyed by the input signals and for transmission of data from the flip-flop outputs to other components of the device or to its input.


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The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


A digital logic circuit that can be in one of two states which it switches (or "toggles") between under control of its inputs. It can thus be considered as a one bit memory. Three types of flip-flop are common: the SR flip-flop, the JK flip-flop and the D-type flip-flop (or latch).

Early literature refers to the "Eccles-Jordan circuit" and the "Eccles-Jordan binary counter", using two vacuum tubes as the active (amplifying) elements for each bit of information storage. Later implementations using bipolar transistors could operate at up to 20 million state transitions per second as early as 1963.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)


An electronic circuit that maintains its 0 or 1 state and is used in static memories and hardware registers. By the mid-20th century, the flip-flop was a breakthrough in circuit logic, which allowed data to be stored. The first flip-flops, known as "trigger circuits," were constructed with two transistors. Subsequent designs use two NOR or NAND logic gates.
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References in periodicals archive ?
The Dumat Al Jandal wind farm will supply electricity according to a 20-year power purchase agreement with the Saudi Power Procurement Company, a subsidiary of Saudi Electricity Company, the Saudi power generation, and distribution company.
But it can't, and so we recognize our own dissatisfaction in Abu Jandal's unresolved restlessness.
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Jandal is now a free man, working as a taxi driver in Yemen.
[2] Poitras takes us remarkably close to Abu Jandal, letting us witness his sense of humor, his sociability, his mania and his piety.
The group holding Fr Sinnott is thought to be a rogue splinter group of the MILF, under the control of a commander called Abu Jandal.
[dagger][dagger] GURNEY, Chris (text) Ross Kinnaird (illus.) Cindy and the Lost Jandal ISBN 9781869438883
Abu Jandal al-Dimashqi, the self-declared leader of Tawhid and Jihad in Syria, also mourned the death of Abu Hureira, the deputy leader of Fatah al-Islam, which has been battling the Lebanese Army in the camp and in Tripoli since May 20.
Hana Abu Jandal pushed past people until she reached a mound of bright orange dirt in the hospital back yard.
Financial close has been reached for Saudi Arabia's 400MW Dumat Al Jandal wind park -- located 896km north of Riyadh, in the Al Jouf region of Saudi Arabia -- that is being developed by a consortium of French renewable energy firm EDF Renewables and Abu Dhabi Future Energy Company (Masdar) at a cost of $500m (SAR1.9bn), with investments secured from Saudi Arabian and international banks.
The Dumat Al Jandal project, being set up at a cost of e1/412.5 million ($14 million), will be Saudi Arabia's first large-scale onshore wind farm and the largest so far in the Middle East, said the company in a statement.