Instructions for using the oscilloscope
1. Oscilloscope measures current
The measurement requires a non-inductive resistor with high precision, small resistance and known value. After measuring the voltage, it is converted into the actual measured current value according to Ohm's law.
2. Oscilloscope measures voltage
(1) The frequency of the measured signal is low: a probe can be used. If the signal amplitude is small and the sensitivity of the 10:1 probe is too low, you can directly connect the Y-axis input end of the oscilloscope to the test point with a shielded wire.
(2) The frequency of the measured signal is higher: using a probe has less distortion and higher accuracy than using a shielded wire or ordinary cable. However, the test distance will be limited by the length of the probe cable, and its sensitivity will decrease with the attenuation of the probe. Generally, coaxial cables can be used when measuring high frequencies.
Measuring AC voltage generally involves measuring the peak voltage of the AC voltage waveform or the potential difference between two points. The measurement results are calculated to obtain the potential difference between the two measured points. That is, the vertical deflection distance between the two measured points on the screen is multiplied by the Y-axis deflection sensitivity, which is the potential difference between the two measured points.
To measure DC voltage, the frequency response of the oscilloscope used must start from DC. First adjust the vertical displacement button so that the scan line is on a certain horizontal scale line as the zero level line, input the measured voltage signal, and measure the vertical distance of the scan line offset from the zero level, that is, the measured DC voltage = vertical deflection Distance × Y-axis deflection sensitivity × probe attenuation coefficient.
3. Oscilloscope measures waveform time
When the oscilloscope's horizontal scan switch is fine-tuned to the calibration position, the scale value of each position of the scan switch indicates the time value represented by the horizontal scale on the screen. Therefore, the oscilloscope can directly measure the entire waveform (or any part of the waveform).
4. Oscilloscope measures frequency
Frequency can be determined using time measurements.
5. Oscilloscope measures phase
Used for dual-trace oscilloscopes, display two light traces on the oscilloscope screen at the same time, measure the distance between the relevant points of the two light traces according to the coordinate scale, and convert the measured distance into a phase difference.
