Flip-flops are often found in electronic circuits. They participate in the operation of many nodes, performing a wide variety of tasks, or can be implemented on different elements, but the principle of their operation remains the same. A special case is the so-called Schmitt trigger, which has proven itself in work. This useful modification of the original circuit quickly gained immense popularity among designers.
There are a variety of options for implementing this idea: a trigger on transistors, operational amplifiers, digital microcircuits, etc. As an example, consider the Schmitt digital trigger, the principle of operation of which will help us to understand this device in general terms. Suppose we have developed a circuit that has two inputs and two outputs. With a combination of input signals 0-1 or 1-0, the output state will change. With all other options, such a device will remember its original state. It would seem, what does the Schmitt trigger have to do with it and what is its idea?
After the invention of the comparator, a device with limiting the input signal and an infinite coefficient, the idea came up to create small devices that would be able to remember the original combination. The first Schmitt trigger was assembled on a comparator. The big disadvantage of such a scheme was the drift of the signal in the trigger area
of the trigger itself. This drawback was eliminated by Schmitt after the introduction of hysteresis into the operation of the circuit. In this case, when a certain level of operation of the device was exceeded, it switched, but it was possible to return to its original state only if it was switched back. In other words, the introduction of hysteresis into the operation of the circuit led to its stable operation. The “bounce” at the output has stopped, it has become inertial and, therefore, reliable in operation. Such a device is called the Schmitt trigger and bears the name of its creator.
The operation of the digital device described above fully meets these requirements. It has a certain trigger threshold. There are voltage levels for each of the states - “zero” and “one”. This is the ideal Schmitt trigger. By introducing a small switching delay, you can get rid of most of the interference that often occurs when operating many devices.
The scope of such devices is quite extensive: they monitor the status of sensors, are used in security alarms, automated systems in production, in the operation of circuitselectronics for various purposes. Probably, many of us turned on slot machines with the help of tokens? To prevent bounce of the microswitch contacts when the token passes through the coin acceptor, a Schmitt trigger is installed in the circuit. It ensures the stable operation of the entire slot machine.
With the development of the element base and manufacturing technology of electronic devices, there is a steady trend towards miniaturization of flip-flops and improvement of their performance.
