Getting started with using an oscilloscope
Panel introduction
1. Brightness and focus knobs
The brightness adjustment knob is used to adjust the brightness of the light trace (some oscilloscopes call it brightness). The brightness should be appropriate when using it. If it is too bright, it will easily damage the oscilloscope tube. The focus adjustment knob is used to adjust the focus (thickness) of the light trace. When using it, the graphics should be clear.
2. Signal input channel
Most commonly used oscilloscopes are dual-trace oscilloscopes, which have two input channels, namely channel 1 (ch1) and channel 2 (ch2). The oscilloscope probes can be connected respectively, then the oscilloscope shell is grounded, and the probes are inserted into the part to be measured for measurement. .
3. Channel selection key (vertical selection)
Commonly used oscilloscopes have five channel selection keys:
(1) ch1: Channel 1 is displayed alone;
(2) ch2: Channel 2 is displayed separately;
(3) alt: two channels are displayed alternately;
(4) chop: two-channel intermittent display, used for dual-trace display when the scanning speed is slow;
(5) add: superimpose the signals of the two channels. During maintenance, channel 1 or channel 2 is usually selected.
4. Vertical sensitivity adjustment knob
To adjust the vertical deflection sensitivity, adjust the position of the knob according to the amplitude of the input signal. Multiply the value indicated by the knob (such as 0.5v/div, which means the amplitude of each division in the vertical direction is 0.5v) by the vertical area of the screen occupied by the measured signal. The number of grids, that is, the amplitude of the measured signal is obtained.
5. Move the adjustment knob vertically
Used to adjust the position of the signal trace under test in the vertical direction of the screen.
6. Horizontal scan adjustment knob
To adjust the horizontal speed, adjust the position of the knob according to the frequency of the input signal. Multiply the indicated value of the knob (such as 0.5ms/div, which means that each grid time in the horizontal direction is 0.5ms) by the number of grids occupied by the measured signal in one cycle, that is The period of the signal is obtained, which can also be converted into frequency.
7. Horizontal position adjustment knob
Used to adjust the position of the signal trace under test in the horizontal direction of the screen.
8. Trigger mode selection
Oscilloscopes usually have four triggering methods:
(1) Normal: When there is no signal, there is no display on the screen; when there is a signal, it displays a stable waveform in conjunction with the level control;
(2) Auto: When there is no signal, the light trace is displayed on the screen; when there is a signal, it cooperates with the level control to display a stable waveform;
(3) Television field (tv): used to display television field signals;
(4) Peak auto (p-p auto): When there is no signal, light traces are displayed on the screen; when there is a signal, a stable waveform display can be obtained without adjusting the level. This method is only used in some oscilloscopes (such as Caltek ca8000 series oscilloscopes).
9. Trigger source selection
There are two types of oscilloscope trigger sources: internal trigger sources and external trigger sources. If an external trigger source is selected, the trigger signal should be input from the external trigger source input terminal. This method is rarely used in home appliance maintenance. If you choose the internal trigger source, generally select channel 1 (ch1) or channel 2 (ch2), which should be selected according to the input signal channel. If the input signal channel is selected as channel 1, the internal trigger source should also select channel 1.
