please tell me http://www.whatisira.com" alt="What Is Ira" target="_blank">what are flip-flops?
[question posted by name2rash]
responses and comments:
In the purest sense, they are on and off switches [oldbuddy]
Thanks for that very simple explaination oldbuddy because when I read through the other answers I got a bit confused. [ossie16d]
There are several types of counter, nearly all of which use a basic element of electronics, the Flip-Flop. The flip-flop is as old as electronics, and is a classic example of the binary system. It has two possible stable states, A or B, and can be 'toggled' from one state to the other, just like a 'push-on, push-off' switch. It was originally made with two vacuum tubes (or one, for example a double triode). It normally has two outputs, one being the complement of the other. That is,if one output(A) is a logic 0, the other(B) is a logic 1, and vice-versa. The input, or Toggle(T) is at logic 0 until a pulse from a sensor, for example, comes along. This pulse takes the logic state to 1, then back to 0. The toggle effect, causing the Flip-Flop to flip, is actually the CHANGE from 0 to 1. In logic terms the flip-flop is made up using AND and OR gates, in logic cicuitry it is just a 'black box' labelled FF. Several FFs may be grouped into yet another black box, a counter, timer, or multivibrator. [shi_2000_21]
I've never heard of the flip flop expression for 'on/off' switches. That's rather novel. [Lackingstyle]
Informal Description of the Invention: A completely molecular computer can be constructed using designed DNA and DNA binding proteins. Several versions of the device are possible. In the simplest device, bacteria or other cells are programmed with DNA sequences and DNA binding proteins that execute logical Boolean operations. It is also possible to construct molecular computers outside cells, but in this case special attention must be paid to providing energy to run the computer. The technology is based on the concept of a molecular flip-flop in which one or more proteins compete for binding to binding sites that overlap. Because only one protein can bind at a time but there are two ways for it to bind, the method can also be used to double the sensitivity of diagnostic assays. Formal Description of the Invention: The present invention is a method and apparatus for molecular computing which provides for molecular logic devices analogous to those of electronic computers, such as flip-flops, AND gates, etc. Coupling of the gates allows for molecular computing. The method allows data storage, the transformation of binary information and signal readout. Possible applications include encoding ``read only'' memory for microscopic identifiers, digital control of gene expression, and quantification of analytes. The computing elements also provide means for complex regulation of gene expression. sorry could not explain in my words ok but this is it [rherdey]
In electronics and digital circuits, the flip-flop or bistable multivibrator is a pulsed digital circuit capable of serving as a one-bit memory. A flip-flop typically includes zero, one, or two input signals; a clock signal; and an output signal, though many commercial flip-flops additionally provide the complement of the output signal. Some flip-flops include a clear input signal, which resets the current output. Because flip-flops are implemented as integrated circuit chips, they also require power and ground connections. Pulsing, or strobing, the clock causes the flip-flop to either change or retain its output signal, based upon the values of the input signals and the characteristic equation of the flip-flop. Strobing here means changing the clock; some flip-flops change output on the rising edge of the clock, and other change on the falling edge. Flip-flops can be split into two main categories: level-triggered and edge-triggered. They can further be divided into four types that have found common applicability in clocked sequential systems: these are called the T ("toggle") flip-flop, the SR ("set-reset") flip-flop, the JK flip-flop, and the D ("Data") flip-flop. The behavior of the flip-flop is described by what is termed the characteristic equation, which derives the "next" (i.e., after the next clock pulse) output, Qnext, in terms of the input signal(s) and/or the current output, Q. The first electronic flip-flop was invented in 1919 by William Eccles and F. W. Jordan (Radio Review Dez 1919 pages 143 following). It was initially called the Eccles-Jordan trigger circuit. The name flip-flop was later derived from the sound produced on a speaker connected with one of the backcoupled amplifiers output during the trigger process within the circuit. USES A flip-flop in combination with a Schmitt trigger can be used for the implementation of an arbiter in asynchronous circuits. Clocked flip-flops are prone to a problem called metastability, which happens when a data or control input is changing at the instant of the clock pulse. The result is that the output may behave unpredictably, taking many times longer than normal to settle to its correct state, or even oscillating several times before settling. Theoretically it can take infinite time to settle down. In a computer system this can cause corruption of data or a program crash. In many cases, metastability in flip-flops can be avoided by ensuring that the data and control inputs are held constant for specified periods before and after the clock pulse, called the setup time (tsu) and the hold time (th) respectively. These times are specified in the data sheet for the device, and are typically between a few nanoseconds and a few hundred picoseconds for modern devices. Unfortunately, it is not always possible to meet the setup and hold criteria, because the flip-flop may be connected to a real-time signal that could change at any time, outside the control of the designer. In this case, the best the designer can do is to reduce the probability of error to a certain level, depending on the required reliability of the circuit. One technique for suppressing metastability is to connect two or more flip-flops in a chain, so that the output of each one feeds the data input of the next, and all devices share a common clock. With this method, the probability of a metastable event can be reduced to a negligible value, but never to zero. The probability of metastability gets closer and closer to zero as the number of flip-flops connected in series is increased. So-called metastable-hardened flip-flops are available, which work by reducing the setup and hold times as much as possible, but even these cannot eliminate the problem entirely. This is because metastability is more than simply a matter of circuit design. When the transitions in the clock and the data are close together in time, the flip-flop is forced to decide which event happened first. However fast we make the device, there is always the possibility that the input events will be so close together that it cannot detect which one happened first. It is therefore logically impossible to build a perfectly metastable-proof flip-flop. Another important timing value for a flip-flop is the clock-to-output delay (common symbol in data sheets: tCO) or propagation delay (tP), which is the time the flip-flop takes to change its output after the clock edge. The time for a high-to-low transition (tPHL) is sometimes different from the time for a low-to-high transition (tPLH). When connecting flip-flops in a chain, it is important to ensure that the tCO of the first flip-flop is longer than the hold time (tH) of the second flip-flop, otherwise the second flip-flop will not receive the data reliably. The relationship between tCO and tH is normally guaranteed if both flip-flops are of the same type. [edit] Flip-Flop integrated circuits Integrated circuit (ICs) can be found with one or two Flip-flop circuits on board. For example, the 7473 Dual JK Master-Slave Flip-flop or the 74374, an octal D Flip-flop, in the 7400 series. [ritzcoolhunk]
In electronics and digital circuits, the flip-flop or bistable multivibrator is a pulsed digital circuit capable of serving as a one-bit memory. A flip-flop typically includes zero, one, or two input signals; a clock signal; and an output signal, though many commercial flip-flops additionally provide the complement of the output signal. Some flip-flops include a clear input signal, which resets the current output. Because flip-flops are implemented as integrated circuit chips, they also require power and ground connections. Pulsing, or strobing, the clock causes the flip-flop to either change or retain its output signal, based upon the values of the input signals and the characteristic equation of the flip-flop. Strobing here means changing the clock; some flip-flops change output on the rising edge of the clock, and other change on the falling edge. Flip-flops can be split into two main categories: level-triggered and edge-triggered. They can further be divided into four types that have found common applicability in clocked sequential systems: these are called the T ("toggle") flip-flop, the SR ("set-reset") flip-flop, the JK flip-flop, and the D ("Data") flip-flop. The behavior of the flip-flop is described by what is termed the characteristic equation, which derives the "next" (i.e., after the next clock pulse) output, Qnext, in terms of the input signal(s) and/or the current output, Q. [mvsandeep]
Flip flops are like registers which is used to store the information in computer.They are nothing but gates.there are various flip flops like JK,RS,T etc.Depending on the output and the design they will be placed in the computer. [mythmoh]
Actually registers are made out of flip-flops. A flip-flop is a one bit memory. So to get an eight bit register, you just use 8 flip-flops. Though flip-flops can be made using any of the digitial gates (ie. and, or, nor, and nand gates), in practice nand and nor are used more to implement flip-flops. [sreejit_p]
flip-flops are engineering terms which are used as memory cells like a D flip flop which has a input,output, preset and clear with a timer[optional] [tanmayangre]