The voltage comparator is a rather interesting device. How does he work? What makes it possible to perform its functions? It is impossible not to note their significant importance in the numerous household appliances that are in abundance in every home.
General information
To control electronic circuits, a large number of different devices are used. They allow branching and customization of signals. To compare two different pulses, a comparator is used. What does he represent? A voltage comparator is a device that compares two different voltages and currents, and based on the data obtained, it produces the final power signal. With its help, a larger value obtained is indicated and the ratio of the obtained parameters is indicated. The device has two analog input terminals that can process negative and positive signals. They also have, like the ADC, one binary digital output. What is its function based on? To ensure operation, a voltage comparator is always created on transistors.
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 a differential voltage within a certain range, which is much lower than the mains voltage. Such devices did not allow the presence of external signals that would go beyond the established limits. A modern analog-to-digital voltage comparator has a transistor input. As a rule, the potential signal for it should not exceed a value of 0.3 V. You can often find a voltage comparator on a microcontroller. For such cases, the products of the Microchip and Atmel companies are used. If you have to deal with a stereo comparator (they are also called ultra-fast type comparators), then the required threshold does not exceed 0.2 V. It should be noted that the value of the used range is limited by a specific input voltage.
Is that all?
Of course not! There is also a voltage comparator on the operational amplifier. It is a device where the difference between input and high signal impedance is extremely finely balanced. Due to this, they are used in cases where it is necessary to ensure the operation of circuits with low voltage. Also, devices that use operational amplifiers are often also called a video spectral comparator. Theoretically, it can work in an open-loop configuration (i.e. no negative feedback). In such cases, the device is usedas 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 a linear mode, when there is no negative feedback. They also feature a fairly significant recovery mode.
- Almost all op amps have internal compensation capacitors that limit the slew rate of the output voltage when generating high frequency signals. Therefore, the use of such circuits leads to a slight delay in the pulses.
- And finally, the comparator has no internal hysteresis.
Because of these shortcomings, the use of a device to control different circuits often does without various amplifiers. The only exception is the use of a generator.
Use
Voltage comparator operation is often used during manufacturing processes where there is limited output voltage. But at the same time, it is necessary that it interact well with digital logic. Therefore, they can often be found in a variety of thermal devices. An example is a temperature switch, a thermostat, and so on. They can also be used to compare signals and resistance for devices such as a stabilizer, timer, and so on. In household devices they containalmost any microchip. The voltage comparator can be found in the microwave, oven, and many other modern appliances.
Working principle
Let's go all the way of the logical "thinkings" of this device. So, initially, an analog signal is supplied to the plus-input. It is called non-invertible. Then we move to the exit. It is called inverted and can send two similar signals of opposite polarity. What determines the decision "adopted" by the device? Let's say the analog input is larger than the output. In this case, we will receive a logical unit. Due to this, for example, 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 greater than the input, the device operates in logic zero mode and nothing happens. In such situations, the reference voltage of the comparator plays a big 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 supply 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, mains voltage sensors. You can find them in many different integrated circuits, where they are used to provide control over input pulses. This maintains communication between the signal source and the destination. The comparator-regulator (trigger) Shimmer is often used. This significant advantage is the ability to work in multi-channel mode, when a significant number of signals can be compared. 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 also 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 small list with answers:
- Initially, you should take care of the development environment. It is possible to recommend to pay 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 to interruptprocess is invalid. Also, while working, it is recommended to save 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 check the data, as well as distribute them to 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 seems possible to buy a ready-made comparator in any radio engineering 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 receive such a moment as the number of channels. You should also carefully inspect the device for external damage. So, it may be damaged during transportation, or it may simply have been poorly executed.
How to test voltage comparator performance
Many novice radio amateurs often have the question of how to find out if the device can be used. For this, you do not need to have some kind of complex circuit or device. To do this, just use a voltmeter. In this case, an adjustable voltage is applied to the inputs and it is determined whether it works or not. We should 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 provide an appropriate connection. In that case, oninverted input applied reference voltage.
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 a radio amateur. You should not be limited to already existing developments. At the same time, it is necessary to learn how to ensure the comparator works with other elements.
