The voltage comparator is a rather interesting device. How does he work? Thanks to what can he fulfill his functions? It is impossible not to note their significant importance in the numerous household appliances, which are in large numbers in every home.
general information
To control electronic circuits, a large number of different devices are used. They allow you to branch and tune the signals. To compare two different pulses, a comparator is used. What is he like? A voltage comparator is a device that compares two different voltages and amperage, and on the basis of the received data it produces a final power signal. With its help, it indicates the higher value obtained and indicates the ratio of the obtained parameters. The device has two analog input terminals that can process a negative and a positive signal. They also have, like the ADC, one binary digital output. What is its functioning based on? To ensure operation, a voltage comparator on transistors is always created.
What is used in modern times
Initially, integrated voltage comparators were widely used. For the characteristic features of their work, they were called high-speed. They require the presence of differential voltage within a certain range, which is much lower than the voltage in the power supply. Such devices did not allow the presence of external signals that would go beyond the established framework. The modern analog-digital voltage comparator has a transistor input. As a rule, the potential signal for it should not exceed a value of 0.3 V. Often you can see the voltage comparator on the microcontroller. For such cases, products of the companies "Microchip" and "Atmel" are used. If you have to deal with a stereo comparator (they are also called ultrafast type comparators), then the required threshold does not exceed 0.2 V. It should be noted that the range used is limited by the specific input voltage.
And it's all?
Of course not! There is also a voltage comparator on the operational amplifier. It is a device in which the difference between the input and the high signal resistance is extremely finely balanced. Due to this, they are used in cases where it is necessary to ensure the operation of circuits with a small voltage. Also, devices that use operational amplifiers are often also called a video spectral comparator. Theoretically, it can work in a configuration where an open loop is provided (that is, there is no negative feedback). The device in such cases is used as a low performance comparator.
What are the disadvantages of comparators with operational amplifiers
They have such negative points:
- So, their main purpose is to work in linear mode, when there is no negative feedback. Also their feature is a rather significant recovery mode.
- Almost all operational amplifiers have internal compensation capacitors, which limit the slew rate of the output voltage when generating high-frequency signals. Therefore, the use of such schemes leads to a slight delay in the pulses.
- And finally, the comparator does not have internal hysteresis.
Because of these shortcomings, the use of a device to control different circuits often dispenses with various amplifiers. The one exception is the use of a generator.
Using
The operation of a voltage comparator is often used during production processes where there is a limited output voltage. But it is necessary that it interacts well with digital logic. Therefore, they can often be found in a variety of thermal devices. An example is a temperature switch, a temperature controller, and more. They can also be used to compare signals and impedances for devices such as a stabilizer, timer, and more. In household devices, almost any microcircuit contains them. A voltage comparator can be found in the microwave, oven, and many other modern pieces of technology.
Principle of operation
Let's go all the way of logical "fabrications" of this device. So, initially the analog signal comes to the plus-input. It is called non-invertible. Then we are transferred to the exit. It is called inverted and can send two bipolar similar signals. What does the “decision” made by the device depend on? Assume the analog input is larger than the output. In this case, we will get a logical unit. Due to this, let’s say, the open collector of the transistor will be turned on or another action will be performed with another element of the circuit. And she will begin to fulfill the functions assigned to her. If the analog output is larger than the input, the device operates in logical zero mode and nothing happens. In such situations, the reference voltage of the comparator plays an important role.
And a little more about the device
Let's pay attention to two-threshold and phase comparators. In the case of their application, almost always the work is based on the impact on the inputs within the logical circuits. And their functioning depends on the level of the power network. We can say that these are rather peculiar elements of the signal transition from analog to digital form. Due to this, it is possible not to specify the uncertainty of the signal outputs. Why? The fact is that the comparator can always provide a certain capture of the hysteresis loop.
Application
Let’s take a closer look at where and how they are used. So, in many houses there is a voltage comparator for discharging the battery on a laptop or phone, scales, voltage sensors. You can meet them in many different integrated circuits, where they are used to provide control over the input pulses. Thanks to this, a connection is maintained between the signal source and the destination. Shimmer comparator-regulator (trigger) is often used. This significant advantage is the ability to work in multi-channel mode, when you can compare a significant number of signals. It provides a very wide functionality (compared to standard comparators). Also, these devices are used to visually determine the state of the surface that is being processed. For these purposes, a roughness comparator is used.
Programming
Comparators are used as part of the PWM circuitry. But not only. They can be used to write individual programs or their components. So, they are often used to create java collections. What is needed for this? Here is a short list with answers:
- Initially, you should take care of the development environment. You can recommend paying attention to Maven. A project is created in it, and the necessary components are selected for it.
- Then additional utilities are installed, and you should start creating a new file. Keep in mind that interrupting the process is unacceptable. Also, during operation, it is recommended to remain at all stages of work.
- When everything is ready, you need to set the required settings.
- Then you need to create a class that will be used to validate the data, as well as their distribution in the desired memory cells. The class is also used to sort certain information by specific parameters and, if necessary, ensure their protection.
How to choose a device when buying
It is possible to buy a ready-made comparator in any radio store. The price for it will depend on the requirements put forward. First of all, you need to decide on the purpose of the device. Then attention should be given to such a moment as the number of channels. You should also carefully inspect the device for external damage. So, it can be damaged during transportation or it was simply performed poorly.
How to check the performance of the voltage comparator
Many beginner hams often ask themselves how to find out if the device can be used. To do this, you do not need to have any kind of complex circuit or device. To do this, it is enough to use a voltmeter. In this case, an adjustable voltage is applied to the inputs and it is determined whether it works or not. Do not forget that devices often contain an output transistor. They have a collector and emitter like "hanging in the air." Therefore, it is necessary to ensure an appropriate connection. In this case, the reference voltage is applied to the inverse input.
Conclusion
So the voltage comparator was considered. This useful device will provide work for a large number of different devices. The comparator will allow you to create many different circuits and significantly expand the field of activity of the ham. It should not be limited to existing developments. In this case, it is necessary to learn how to ensure the work of the comparator with other elements.