In the effective frequency range, the measured value of the true RMS multimeter corresponds to the root mean square value measured by the oscilloscope; the measurement error of the oscilloscope is 3%, and the measurement accuracy of the general multimeter is higher. 

1.The power supply needs to be fully loaded and output;

2.Oscilloscope channel setting: channel coupling is "AC", bandwidth limit is 20MHz, attenuation ratio × 1; probe setting is 1 × file;

3.Adjust the oscilloscope to the appropriate vertical deflection coefficient and time base gear;

4.To avoid interference, a short spring can be used for the grounding terminal, as close as possible to the output terminal of the power supply;

5.It is recommended to measure the peak-to-peak value of ripple through the cursor; 

Due to the influence of environmental factors, the measurement error is too large,

 you can try to use the "self-correction" function of the oscilloscope. 

User can install the setting as the following steps：

1、Set storage depth to maximum.

2、According to observing time to put timebase on the proper position. If user want to observe it for 1S, then set timebase to 100ms/Div, screen time is 100ms*14 grid=1.4s.

3、Select trigger mode as single trigger. When wave meets the trigger condition, wave will be captured and stably display on the screen.

In a sense, it's ture. Higher bandwidth means the ability to accurately measure signals at higher frequencies, which is good in some cases However, it really depends on the user scenario, higher bandwidth is not necessarily better. 

The measured signal is not periodic, it need to set the relevant parameter based on the basic characterstic of signal by manual regulation to acquire waveform.            

Parameters such as signal frequency or amplitude are too low. 

User may see a sine wave with the same frequency when testing a square wave.                                                                                                        This  case does not necessarily represent  a failure of the oscilloscope. It may have been influenced by the high-frequency harmonic component of the composition of the square wave itself. 

To better understand this issue, it is need to study the effect of harmonics on square waves

For example, a 25MHz square wave will be treated as a 25MHz sine wave by the UTD2052CL. Although the square wave frequency is the upper limit of frequency bandwidth of oscilloscope, its harmonic components are already beyond the -3dB high frequency cutoff of the oscilloscope. Due to this natural cutoff, the main harmonic component of the square wave exceeds the second harmonic component (2 * 25 = 50 MHz). And it is naturally filtered out. The 3rd and 5th harmonic components are respectively 75 MHz and 125 MHz center frequencies. This is far more beyond the upper bandwidth limit of the oscilloscope.

In order to be able to view a square wave signal on an oscilloscope, the 3rd and 5th harmonic components of the square wave must not exceed the upper bandwidth limit of the oscilloscope.

When test a low frequency signal (below 100Hz), input channel coupling should set to be "DC", if it set as "AC", it may occurs signal distortion, then square wave may turn to triangle wave.

Why is the phase difference displayed incorrect when measuring two signals with a phase difference of 180° or other phase differences?

If user need to measure two signal's phase difference, trigger mode should set to "single trigger", then it can correct measure two channel's phase difference.

If the instrument has connected with upper computer, the instrument will turn into remote control mode, press Local key to exit this mode.

If the instrument is not connected with upper computer, insert incompatible U disk may cause system broken down and screen stucked. Reboot the instrument to fix it.

If the instrument is not connected with upper computer and not insert incompatible U disk, the instrument occurs keypad failure frequently, check the keypad lock function is normal, if it is, please contact with after sales department to send the instrument back to factory for check and maintenace.

Because there are multiple signalsthat meet the trigger conditions in one cycle, the oscilloscope triggers at different locations and the waveforms will overlap. By adjusting the trigger hold off to a slightly smaller value of the cycle, this problem can be improved.

The role of the oscilloscope trigger hold off : according to the user-defined hold off time to delay triggering. Mainly for a cycle of multiple signals that meet the trigger conditions, after seting the trigger hold off time, the first point to meet the conditions will not be triggered, it will be triggered after the hold off time to meet the trigger conditions. In this way, it can be fixed-point trigger according to the needs of users.

Analog oscilloscope is mainly made of battery lead plate, electronic gun and other analog circuit technology; digital oscilloscope is mainly made of A/D and other digital circuit technology.

Different bandwidth: affected by the electronic offset speed, the bandwidth of the analog oscilloscope can only reach several hundred hertz, while the digital oscilloscope bandwidth has exceeded 100 GHz  

Different function: digital oscilloscope can stable view continous periodic siganl and have automatic measurement, wave storage, wave analysis, multiple wave trigger, remote control and other functions.

Different stability: analog oscilloscope is made of analog components, indicators discrete and temperature excursion will have more serious impact; analog oscilloscope are relatively Larger in size; analog oscilloscope can capture real-time waveform, digital oscilloscope may cause segment wave loss when processing, but with the improvement of ADC speed and processing algorithm, the waveform capture rate has been able to meet the needs of use.

Ramp Time is refers to the time required for the voltage to be measured to increase slowly from 0V to the rated test voltage. In oscilloscope, it generally refers to the time to increase from 10% to 90%.

The better way is to select differential prob, it can measure the most accurate signal. 

If there are no differential prob, then user can use two single probe to connect with channel (CH1, CH2) of digital oscilloscope, processing mathematical operation to get CH1-CH2 waveform and analyse it. Keep the two probe and the vertical position of two channel are the same as can as possible, otherwise, the error will be large.

Like detect small signal of audio frequency amplifier,  noise wave of power supply.

① Matter of oscilloscope grounding : oscilloscope chassis and refernce ground wire of probe should  to be reliably grounded, good grounding is the primary condition for measuring interference.  

② Interference matter of introduced by the reference ground wire of the oscilloscope: since ordinary probes usually have a section of ground wire that will form an interference path similar to a loop antenna with the point to be measured, it may introducing relatively large interference. So it is important to minimize this interference. The method that can be used is to take off the probe cap and not use the ground lead on the probe, but directly use the probe tip and the location inside the probe to contact the point to be measured for measurement.

③ Use differential measurement way to eliminate common-mode noise.