How to measure ultra-low frequency waveforms with a Tektronix oscilloscope

In our daily debugging of circuit boards and measurement , when initializing the oscilloscope , we often "get lazy" and just press the "Auto Set" button on the oscilloscope.

However, have you ever encountered a situation where you need to measure ultra-low frequency waveforms? For example, below 2Hz , or even below 1Hz ? At this time, the "auto setting" will not work. The following example will illustrate how to measure ultra-low frequency waveforms:

Next, we measure a sine wave with a frequency of 0.7 Hz and a Vpp of 3.5 (assuming we don’t know what waveform it is at the beginning and need to measure to find out).

What happens when we press the "Autoset" button on the oscilloscope? Let's take a look at its waveform:

What kind of waveform is this? Isn't it just no waveform? Haha, don't worry, don't let the false image of the oscilloscope confuse you. At this time, the frequency is too low. If the oscilloscope sampling display cannot keep up, it will be like there is no waveform. Then let's take a look, adjust the "Seconds / Division" button to reduce the number of grids per second, and then adjust the "Volts / Division" button to see the effect:

Can you clearly see that it is a sine wave? Haha, careful friends can also see that due to the display method of the oscilloscope, part of the waveform on the screen is black, which is related to the scanning method of the oscilloscope.