Voltage measurement method
Before measurement, adjust the brightness and focus to the best state to facilitate the readout, and the waveform display as large as possible to reduce the time error; if using a probe, check the capacitance correction.
(1) Measurement of DC voltage. Put the AC-GND-DC switch to GND, the position is at zero level to facilitate observation on the screen, this position is not necessarily in the center of the screen.
Put VOLTS/DIV at an appropriate level and set the AC-GND-DC switch to DC. At this time, since the scan line only moves on the DC voltage line, the DC voltage signal can be obtained by multiplying the VOLTS/DIV value by the moving width. If VOLTS/DIV is 50 mV/div, the calculation result is 50 mV/div x 4.2 div = 210 mV. But if the probe (10:1) is used, the actual value should be multiplied by 10 times, that is, 50 mV/div x 4. 2 div x 10-2 100 mV = 2. 1 Vo
(2) Measurement of AC voltage. Like the DC voltage measurement, the zero level can be placed anywhere that is convenient for inspection.
If VOLTS/DIV is 1 V/div, the calculation formula: IV/div x5 =5*_p, but if the probe (10:1) is used, the actual value is 50. In addition, if the small amplitude signal is superimposed on the DC voltage, it is convenient To amplify the signal while observing, the AC-GND-DC switch can be placed on the AC, without direct current, which can improve the sensitivity of observation.
(3) Measurement of frequency and period. The signal period is 4 points and 8 points, which is 2 grids on the screen. The scan time is assumed to be 1 ms/div, and the period is 1 ms/div x 2.0 div = 2.0 mso, so the frequency is 1/2. 0 ms = 500 Hz, but if xlO MAG (x5 MAG) is used, the scan is To zoom in, TIME/DIV must be converted to the indicated value of 1/10 (1/5).
(4) Measurement of time difference. In order to measure the time difference between the two signals, a signal is placed on the synchronization signal, and there is a signal A. If the synchronization signal source is placed on CH1, and the synchronization signal source is added to CH2, please refer to the manual for details here. Therefore, in order to determine the delay time of the CH1 signal to the CH2 signal, add the synchronization signal source to CH1, and vice versa.
In other words, select a phase-leading signal as the synchronization signal source. If the opposite is true, the part to be tested may not be displayed on the screen. If this happens, measure the amount between the 50% points of the two signal amplitudes displayed on the screen, and the two signal amplitudes can overlap.
Note: Since the pulse wave contains a lot of high-frequency components (harmonics), you must carefully consider the operation. When measuring harmonic signals, use probes or coaxial cables to make the grounding wire as short as possible
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(5) Measuring rise (fall) time “When measuring the rise time of a pulse, pay attention to the measurement error. The rise time Tn of the waveform to be measured, the rise time 7 of the oscilloscope; there is a relationship between the rise time displayed on the screen,
If the rise time of the measured pulse is much longer than the rise time of the oscilloscope, the relationship between the measurement error and the rise time of the oscilloscope can be ignored. If the rise times of the two are similar, measurement errors will occur.
The actual rise time is 丿尊* In addition. When there is no waveform distortion, the following relationship exists between the frequency band and the rise:
f,. xt, =0.35
Where X-frequency band, Hz;
t,–rise time, s.
(6) Synchronization of composite waveforms. If different amplitudes appear alternately, whether the waveforms overlap or not depends on the set level. If the trigger level is selected on the line, 4, B, C,. , E, F…starting from 4 and E, F, G, H, Pi…starting from £, appear alternately, because the lines overlap and synchronization cannot be achieved. At this time, if the level is turned clockwise to the Y line Trigger level, the waveform displayed on the screen is R, C, D, E, and eight••appear alternately starting from B, synchronization can be achieved,
(7) Waveform coordination when measuring with two channels.
① If the CH1 and CH2 signals are synchronized, or the two signal frequencies have a certain time relationship, such as a fixed proportional relationship, set the TRIG signal source switch to INT, otherwise, set it to CH2.
②If the observed signals do not have a synchronized relationship, you can set the TRIG signal source switch to INT, and the synchronization signal changes alternately with the system, so the waveform of each channel is stable and synchronized.
If a sine wave is sent to CH1 and CH2, to expand the synchronization level range, put the CH2 axis input coupling to AC coupling. In addition, if the amplitude of the displayed signal is small, you can switch the VOLTS/DIV switch to increase the amplitude.
