Playing with an oscilloscope, you have to understand these twelve details!

The oscilloscope is a very versatile electronic measuring instrument. It can convert electrical signals that are invisible to the naked eye into visible images, which is convenient for people to study the changing process of various electrical phenomena. The oscilloscope uses a narrow electron beam composed of high-speed electrons to hit the phosphor-coated screen to produce a small light spot (this is the working principle of a traditional analog oscilloscope). Under the action of the measured signal, the electron beam is like the tip of a pen, which can draw the change curve of the instantaneous value of the measured signal on the screen. The oscilloscope can be used to observe the waveform curves of various signal amplitudes changing with time, and it can also be used to test various electric quantities, such as voltage, current, frequency, phase difference, amplitude modulation, and so on.
1. What are the valuable indicators of an oscilloscope?
Bandwidth, grade level parameters, the increase in bandwidth is also grade level.
2. How high is the sampling rate to satisfy?
Generally speaking, the sampling rate is 5 times the bandwidth. For example, a 200M bandwidth oscilloscope can be equipped with a 1G sampling rate.
Pursuing a higher sampling rate is nothing more than catching small glitches, but these high-frequency glitches have been filtered out in the bandwidth layer, and a higher sampling rate does not bring good benefits.
3. What is the difference between normal trigger and automatic trigger?
Normal: Normal (standard) trigger, the waveform will be sampled only if there is a trigger event that meets the conditions;
Auto: Automatic triggering. After waiting for a period of time, if no trigger event that meets the conditions occurs, it will be forced to trigger and sample the waveform;
Since the trigger position is random, it often leads to unstable waveform display. If the above situation occurs, please use Normal mode.
4. How to catch abnormal signals whose conditions cannot be determined?
You can use template triggering to capture.
When the template trigger is turned on, the template actually comes as a layer. It will continuously detect whether a waveform touches the area of the template. When a waveform touches the template, it will detect a signal, and then It will be filtered and displayed.
5. Is the channel of the oscilloscope isolated?
The channel of the oscilloscope is not isolated; the ground of the oscilloscope is connected to the earth, not directly connected to the neutral line;
It is true that the addition of an isolation transformer can directly measure 220V mains, but it is not a recommended method. The safe and correct method should be to use a differential probe.
6. Which standard is the voltage measuring oscilloscope and multimeter?
The vertical resolution of a general-purpose oscilloscope is 8bit. The measurement accuracy is related to the vertical resolution and vertical gear.
The accuracy of the multimeter is much higher. The ADC of the six-and-a-half-digit multimeter can reach 24 bits, and the handheld meter is far more than 8 bits. The voltage value measured by the multimeter is more reliable.
7. What is the difference between the X1 and X10 positions of the oscilloscope probe?
There are two points:
The attenuation bandwidth is different, the signal amplitude of the X1 gear is not attenuated, and the signal at the X10 gear is attenuated to one-tenth of the original;
The bandwidth is different, the bandwidth of the X1 gear is only about 10M, while the bandwidth of the X10 gear is about 250M.
8. Do general oscilloscope probes need to be calibrated regularly?
The standard does not have clear measurement regulations for probes, but for passive probes, at least when the probe is replaced or the probe is exchanged channels, probe compensation adjustments must be made.
9. What are the main factors that determine the price of oscilloscope probes?
The main determinants of price are of course bandwidth and features.
There are many types of oscilloscope probes with different performances, such as high voltage, differential, active high-speed probes, etc., and the price ranges from a few hundred RMB to close to ten thousand US dollars.
The probe is the part of the oscilloscope that contacts the circuit. A good probe can provide the fidelity required for testing. To achieve this, even passive probes must have a lot of passive component compensation circuits (RC networks) inside.
10. Is there a way to use an oscilloscope to measure the working condition of a high-frequency transformer or inductor core?
You can rely on the power analysis software that comes with the oscilloscope to do it. There is a function-B-H curve analysis, which can reflect the working state of the magnetic core, measure the dynamic inductance value, and get the magnetic core loss.
11. Can the oscilloscope perform Fourier decomposition?
Most modern digital oscilloscopes have FFT function, but you need to pay attention to the number of points that FFT can analyze, which directly determines the accuracy of FFT analysis results and avoids spectrum leakage.
12. Can the oscilloscope perform filtering processing? Such as low-pass filtering of the PWM wave?
Oscilloscopes generally have a bandwidth limit of 20MHz. This is a hardware filter. Some oscilloscopes also support software filters with adjustable cutoff frequencies.