高校实验器材使用演示

We will now move from theory to practice and demonstrate the instrument's operation through an actual measurement. Step 1: Initial Self-Test.Before measuring any external signal, it is essential practice to perform a quick self-test. This verifies the integrity of your oscilloscope channel and probe using the built-in Probe Compensation Signal. Procedure for Channel 1: Connect the Probe: Attach your probe to the CH1 input. Connect the probe tip to the dedicated Probe Compensation Signal Output terminal. Connect the probe's ground clip to the adjacent Ground terminal. Auto-Set the Signal: Press the front-panel AUTO button. The oscilloscope will automatically analyze the signal and optimize the vertical scale, horizontal timebase, and trigger settings. A stable, clean square wave should now be displayed. This is the expected output. Confirms that Channel 1 and the probe are functioning correctly.Now, let's confirm the self-test waveform's key parameters using the Automatic Measurement function. Press the MEASURE button.On the touchscreen, tap Add Measurement.Navigate to the Horizontal parameters and select Frequency.Navigate to the Vertical parameters and select Peak-to-Peak. After adding these measurements, their readouts will appear at the bottom of the screen. The probe compensation signal should yield values approximately matching:Frequency is 1 kilohertz. Peak-to-Peak Voltage is 3 volts.A stable square wave displaying these expected parameters confirms that both the oscilloscope's Channel 1 and the connected probe are operating correctly. This completes the self-test procedure.Next, we will demonstrate the oscilloscope's operation using a real signal. A key objective is to observe the relationship between a signal's DC offset and the input coupling mode selected on the oscilloscope channel. First, we will generate a known test signal using the oscilloscope's built-in waveform generator.Click G1and select sine wave. We will configure it to output a 1kilohertz sine wave with a 3 volt peak-to-peak amplitude and 0 volt DC offset. We will then measure this signal on Channel 1.Now, connect the waveform generator's output to Channel 1 of the oscilloscope: connect the red clip to the red terminal, and the black clip to the black terminal.To help you become familiar with manual operation, we will now demonstrate manual waveform adjustment. Press the Vertical OFFSET knob to reset the vertical offset to zero. Rotate the Vertical SCALE knob for Channel 1 counterclockwise to set the vertical scale to 1 volt per div. You can also adjust the Horizontal SCALE knob to display more cycles on the screen. Let's measure the waveform's maximum and minimum values, which are approximately 1.5 volt and negative 1.5 volt.If the oscilloscope displays an unstable waveform during an experiment, you can quickly stabilize it by pressing the LEVEL knob in the trigger control section. This action automatically sets the trigger level to the midpoint of the waveform's amplitude range. When performing simultaneous multi-channel measurements, always first select the channel with the largest amplitude signal as the trigger source, then adjust the trigger level. This procedure ensures a stable display for all observed waveforms.Now, set the signal source's voltage offset to 0.5 volt. Observe the screen: the entire waveform shifts upward by 0.5 volt. Consider: Which coupling mode is active? This confirms we are in DC coupling mode. Only in this mode do both DC and AC signal components pass through, allowing the waveform to shift vertically with the offset. Next, switch the coupling to AC mode and observe. The sine wave shifts back down by 0.5 volt, returning to its original position. This is because AC coupling blocks the DC component—the added 0.5 volt offset is filtered out, leaving only the AC signal.When selecting the input channel coupling mode of an oscilloscope, please keep the following key points in mind: When measuring signals with DC offset, always use DC coupling. Under AC coupling, the tested waveform may not reflect the true characteristics of the signal, since AC coupling can filter out the DC offset component. Please note that regardless of whether you are using AC or DC coupling, always observe the position of the zero level when analyzing the waveform. This helps you form a complete understanding of the waveform before proceeding with any measurements. An oscilloscope is an indispensable instrument in electronic measurement. We hope every student can master its operation proficiently. That concludes the content of this video. Thank you all.