Today, often instead of making an oscilloscope from a computer, for example, most people prefer to simply purchase a USB oscilloscope. But, going shopping, you can see that the price of budget oscilloscopes starts at $ 200. And serious equipment is worth several times more expensive. Those people who are not satisfied with this price, the easiest way to make an oscilloscope from a laptop or computer with their own hands.
1 What to use
- 1.1 On a note
- 1.2 "Avangard"
- 1.3 How to use it
2 Electrical circuit
- 2.1 How to choose a voltage divider resistors
- 2.2 Voltage Divider Trimmer Resistors
- 2.3 How to choose ordinary resistors
- 2.4 Resistor fit
- 2.5 What to consider
What to use
The most optimal today is Osci program, it has an interface similar to a classic oscilloscope: the monitor is a standard grid, with which you can measure the amplitude or duration.
Among the shortcomings of this program, we can highlight the fact that it works a bit unstable. During operation, the utility may sometimes hang, and in order to reset it, you need to use the specialized TaskManager. But all this is compensated by the fact that the program has a familiar interface, and is quite easy to use, as well as has a large number of functions, they provide an opportunity to make a fully working oscilloscope from a computer or laptop.
On a note
It must be said that in the software bundle there is special low-frequency generator, but its use is undesirable, it tries to completely control the sound card driver operation, which provokes sound deactivation. If you decide to try it out, make sure you have a recovery point or backup your OS. The best way to do an oscilloscope from a computer with your own hands is to download a working generator.
This is a domestic program, it does not have the usual and standard measuring grid, and is different a very large screen for taking screenshots, but at the same time allows you to use set frequency meter and voltmeter amplitude values. This partially compensates for the disadvantages indicated above.
Having made this oscilloscope from a computer, you will come across the following: at small levels of indicators a voltmeter and Frequency meter can significantly distort the data, but for beginners to radio amateurs, this utility will be quite sufficient. Another useful feature is that you can do an absolutely independent calibration of the two existing scales of the installed voltmeter.
How to use it
Due to the fact that the input circuits of the sound card have a special coupling capacitor, the computer as an oscilloscope can work only with closed entrance. Thus, only the variable component of the indicators will be visible on the monitor, but, having a certain dexterity, with the help of these programs you can make a measurement of the constant component index. This is very important in the case when, for example, the reference time of a multimeter does not allow fix a certain value of the amplitude of the voltage on the capacitor being charged using a large resistor.
The lower voltage value is limited by background and noise levels and has approximately 1 mV. The upper limit is limited only by the indicators of the divider and reaches more than a hundred volts. The frequency range is limited by the very possibility of a sound card for old computers. is about 20 kHz.
Naturally, in this case, a rather primitive device is considered. But when you do not have the opportunity, for example, to use a USB oscilloscope, then in this case its use is quite acceptable. This device will help you in repairing various audio equipment, or can be used for educational purposes. In addition, the oscilloscope program will allow you to save a plot for illustration of the material or for placement in the network.
If you need a prefix to the computer, then it will be much more difficult to make an oscilloscope. Today, on the Internet, you can find a fairly large number of different schemes of these devices, and to manufacture, for example, a two-channel oscilloscope, you will only need to duplicate them. The second channel is often relevant in the case when it is necessary to compare two signals or the oscilloscope is used to connect external sync.
As a rule, the schemes are very simple, but so, you yourself will provide a very large range of available measurements using a minimum of radio components. And the attenuator, which is made according to the classical scheme, would require you to have highly specialized high megohm resistors, and its input resistance all the time changed when range switching. Therefore, you would experience some limitations when using conventional oscilloscopic wires designed for an input impedance of no more than 1 megohm.
How to choose a voltage divider resistors
Due to the fact that often radio amateurs have difficulty in choosing precision resistors, it often happens that you have to choose a wide profile devices that need to be as closely as possibleotherwise you won't be able to make an oscilloscope from your computer with your own hands.
Voltage Divider Trimmer Resistors
In this case, each divider arm has two resistors, one is constant, the other is trimmer. The minus of this option is its cumbersome, but the accuracy is limited only by what available characteristics the measuring apparatus has.
How to choose ordinary resistors
Another option to make an oscilloscope from a computer is to select a pair of resistors. Accuracy in this case is ensured by the fact that pairs of two sets are used with a fairly decent spread. Here it is important to initially perform thorough measurements of all devices, and then pick up pairs, the total resistance of which will be most suitable for your circuit.
Today, fitting resistors by removing parts of a film is often used even in modern industry, that is, an oscilloscope is often made from a computer.
But I must say that if you want to customize high-resistance resistors, then the resistive film should not be cut through. Since in these devices it is located on a cylindrical surface in the form of a spiral, therefore, it is necessary to make a filing very carefully so that not to break the chain. Then:
- To adjust the resistors at home, you just need to use ordinary sandpaper "null".
- Initially, the resistor, which has less resistance, carefully removes the protective paint layer.
- Then you need to solder the resistor to the ends, they are glued to the multimeter. With the help of accurate sandpaper movements, the resistance values of the resistor are displayed to the desired value.
After when the resistor is fully fitted, propyl place covered with a layer of special protective varnish.
Today, this method is the fastest and easiest, but it also gives good results, which made it optimal for home conditions.
What to consider
There are a number of rules that must be fulfilled in any case, if you decide to carry out these works:
- The oscilloscope computer used must be grounded.
- Do not connect ground to the outlet. It is connected through a special case of the linear input connector with the case of the system unit. In this case, regardless of whether you are in a phase or zero, you will not have a closure.
In other words, only a wire can be plugged into the outlet, which connects to resistor, and is in the adapter circuit with a nominal value of one meg. If you try to plug a wire into the network that is in contact with the case, then in almost all cases this will necessarily lead to the most disastrous consequences.