The oscilloscope is a high-performance electrical and electronic measuring instrument manufactured through the acquisition of data, after the A/D conversion, and through a series of techniques such as software programming. Mainly oscilloscope, vertical deflection system and horizontal deflection system and host composition. It can display and observe the trajectory change of the monitored signal on the screen in a graphic way, and is one of the most commonly used electronic measuring instruments. Below I will give you a brief introduction about the principle of oscilloscope and the use of the relevant content. I hope you can help.
A.? The working principle of the oscilloscope
Oscilloscopes use a narrow, high-speed electron beam composed of electrons, hitting the screen surface coated with fluorescent material, can produce a small point of light, under the action of the signal under test, the electron beam on the screen surface depicts the instantaneous value of the signal to be measured the curve of the change, to facilitate the study of a variety of electrical phenomena in the process of change.
? ? Second, the use of oscilloscopes
With oscilloscopes can observe a variety of different electrical signal amplitude over time waveform curves, on the basis of which oscilloscopes can be applied to the measurement of voltage, time, frequency, phase difference and amplitude modulation of electrical parameters. The following describes the use of oscilloscopes to observe the waveform of electrical signals using the steps.
1?Oscilloscope and power supply system
1)Power supply: oscilloscope main power switch. When this switch is pressed, the power indicator light is on, indicating that the power supply is on.
2)Glow: rotating this knob can change the brightness of the light spot and scan line. It can be smaller when observing low-frequency signals and larger when observing high-frequency signals.
3)Focus: the focus knob adjusts the size of the electron beam cross-section, and focuses the scan line into the clearest state.
4)Scale Brightness: This knob adjusts the brightness of the illuminator behind the fluorescent screen. Normal indoor light, the illumination darker good. In the environment of insufficient indoor light, the lighting can be adjusted appropriately bright.
2?fluorescent screen
According to the measured signal on the screen occupied by the number of frames multiplied by the appropriate constant of proportionality can be derived from the voltage value and time value. According to the selection of the input channel, the oscilloscope probe will be inserted into the corresponding channel socket, the ground on the oscilloscope probe and the ground of the circuit under test are connected together, and the oscilloscope probe is in contact with the point under test. There is a two-position switch on the oscilloscope probe. When this switch is set to the "X1" position, the measured signal is sent to the oscilloscope without attenuation, and the voltage value read out from the fluorescent screen is the actual voltage value of the signal. This switch is dialed to the "X10" position, the measured signal attenuation for 1/10, and then sent to the oscilloscope, the voltage value read from the fluorescent screen multiplied by 10 is the actual voltage value of the signal.
3?Vertical Deflection Factor and Horizontal Deflection Factor
There is often a small knob on each band switch to fine-tune the vertical deflection factor for each gear. Turn this knob fully clockwise to the "calibration" position, where the vertical deflection factor value matches the value indicated by the band switch. Turn this knob counterclockwise to fine-tune the vertical deflection factor. It should be noted that the fine adjustment of the vertical deflection factor may cause inconsistency with the value indicated by the band switch. The oscilloscope's standard signal source, CAL, is used exclusively for calibrating the oscilloscope's time base and vertical deflection factor. The displacement knob on the front panel of the oscilloscope adjusts the position of the signal waveform on the fluorescent screen.
4?Input Channel and Input Coupling Selection
1)Input Channel Selection - There are at least three ways to select the input channel: channel 1, channel 2, and dual channel.
When selecting channel 1, the oscilloscope only displays the signal of channel 1; when selecting channel 2, the oscilloscope only displays the signal of channel 2; when selecting dual channels, the oscilloscope displays the signals of channel 1 and channel 2 at the same time. In maintenance, channel 1 or channel 2 is chosen more often.
2) Input coupling mode Input coupling mode - AC, ground current, DC.
5?Trigger
(1)Normal: when there is no signal, there is no display on the screen; when there is a signal, with the level control with the display of stable waveforms;
(2)Automatic: when there is no signal, the screen displays the light traces; when there is a signal with the level control with the display of stable waveforms;
(3)TV field: used to display the TV field signal;
(4)Peak Auto: when there is no signal, the screen displays light traces; when there is a signal, there is no need to adjust the level to obtain a stable waveform display.
6?Scanning mode
The scanning has three scanning modes: automatic, normal and single.
Examples:? Amplitude and frequency measurement method (to test the calibration signal of the oscilloscope as an example)
(1) Insert the oscilloscope probe into the channel 1 jack, and place the attenuation on the probe in the "1" file;
(2) Place the channel selection in CH1, and the coupling mode in the DC file;
(3) Insert the probe into the small hole of the calibration signal source, and at this time, the screen of the oscilloscope appears to be a light trace;
(4) Insert the probe into the calibration signal source. light trace;
(4)Adjust the vertical knob and horizontal knob to stabilize the waveform displayed on the screen, and place the vertical trim and horizontal trim in the calibration position;
(5)Read out the number of frames occupied by the waveform in the vertical direction, multiply it by the indicated value of the vertical attenuation knob to get the amplitude of the calibration signal;
(6)Read out the number of frames occupied by the waveform in the horizontal direction for each cycle, multiply it by the indicated value of the horizontal scanning knob to obtain the amplitude of the calibration signal;
(7)Read out the number of frames occupied by the waveform in the horizontal direction for each cycle, multiply it by the indicated value of the horizontal scanning knob to obtain the amplitude of the calibration signal. (6) read the waveform each cycle in the horizontal direction of the number of frames, multiplied by the indication of the horizontal scanning knob value, get the period of the calibration signal (the inverse of the period of the frequency);
(7) the general calibration signal frequency of 1kHz, amplitude of 0.5V, used to calibrate the oscilloscope internal scanning oscillator frequency, if it is not normal, the oscilloscope should be adjusted (internal) the corresponding potentiometer, until consistent with so far.
Three, the oscilloscope use of caution
(1) hot electronic instruments in general to avoid frequent power on and off, the oscilloscope is also so.
(2) for quantitative measurements, the oscilloscope should be energized for more than 10 minutes to warm up, so that the components in the machine work in a thermally stable state, otherwise due to the temperature of the components in the machine is in the process of rising, affecting the results of the measurement.
(3) If the waveform is found to be disturbed by the outside world, ground the oscilloscope case.
(4) When observing and adjusting the bright spots on the screen, the brightness of the spots should be moderate and not too bright.
(5) The voltage of "Y input" should not be too high to avoid damage to the instrument, and should not exceed 400?V at maximum attenuation.
(6) Before turning off the power, turn the glow knob to the end in the counterclockwise direction, so that the brightness is reduced to a minimum, and then disconnect the power switch.
The above is about the principle of oscilloscopes and oscilloscopes and other aspects of the content of the introduction, I hope that the introduction of the above content can help you. For the oscilloscope principle of understanding can make us more convenient to use and regulate the oscilloscope. At the same time it is more widely used, through the above one by one introduction I believe that you can be a good understanding of the use of oscilloscopes. Now more types of oscilloscopes, relative to foreign brands, many domestic brands are also a good choice. I hope that the above introduction can bring you help.