Oscilloscopes are direct substitutes for the multimeters. What a multimeter can do, oscilloscopes can do it better. And with the increase in functionality, the using of an oscilloscope is way more complicated than the multimeters, or any other electronic measuring tools.
But, it’s not definitely rocket science. Here we will discuss the basics you need to know while operating an oscilloscope. We’ll cover the least of the things you need to know to get your job done with oscilloscopes.
Important Parts of an Oscilloscope
Before we jump into the tutorial, there are a few things you need to know about an oscilloscope. As it is a complicated machine, it has a lot of knobs, buttons for its complete functionality.
But hey, you don’t have to know about every one of them. We will discuss the most important parts of a scope that you have to know about before you get going.
An oscilloscope is only good if you can actually connect it to a signal, and for that you need probes. Probes are single-input devices that route a signal from your circuit to the scope.
Typical probes have a sharp tip and a ground wire with it. Most of the probes can attenuate the signal up to ten times the original signal to provide better visibility.
Best oscilloscopes have two or more channels. There is a dedicated button beside every channel port to select that channel. Once you select it, you can view the output on that channel.
You can view two or more output simultaneously if you select more than one channel at a time. Of course, there has to be signal input on those channel port.
The trigger control on the oscilloscope sets the point at which the scan on the waveform starts. In simple words, triggering stabilizes the output we see in the display.
On analogue oscilloscopes, only when a certain voltage level had been reached by the waveform would the scan start. This would enable the scan on the waveform to start at the same time on each cycle, enabling a steady waveform to be displayed.
This control on the oscilloscope alters the gain of the amplifier that controls the size of the signal in the vertical axis. It is controlled by a round knob having different levels marked on it.
When you will select the lower limit, the output will be small on the vertical axis. When you will increase the level, the output will be zoomed in and be easy to observe.
This determines the position of the horizontal axis. You can select the position of it to observe the signal on any position of the display. This is important to measure the amplitude level of your signal.
It controls the speed at which the screen is scanned. From this, the period of a waveform can be calculated. If a full cycle of a waveform to 10 microseconds to complete, this means that its period is 10 microseconds, and the frequency is the reciprocal of the time period, i.e. 1 / 10 microseconds = 100 kHz.
This is used to hold the signal from varying over time. This helps to observe rapid moving signal more conveniently.
Brightness & Intensity Control
They do what they say. There are two associate knobs in every scope that lets you control the screen brightness and adjust the intensity of the signal you are observing on the display.
Working with an Oscilloscope
Now, after all the preliminary talks, let’s turn on the scope and begin the actions. No rushing, we will go step by step:
- Plug in the chord and turn on the scope pressing the on/off button. Most of the modern oscilloscope have them. The obsolete ones would turn on only by plugging it in.
- Select the channel you are gonna work with and turn off the others. If you need more than one channel, select two and turn off the rest like before. Change the ground level wherever you want and remember the level.
- Connect the probe and set the attenuation level. The most convenient attenuation is 10X. But you can always choose according to your wish and signal type.
- Now you need to calibrate the probe. Normally you would just plug the oscilloscope probe in and start to make measurements. But oscilloscope probes need to be calibrated before they are sued to ensure that their response is flat.
To calibrate the probe, touch the pointy tip to the calibration point and set the voltage per division to 5. You will see a square wave of a magnitude of 5V. If you see any less or more than that, you can adjust it to 5 by rotating the calibration knob.
Although it is a simple adjustment, it is essential that it is undertaken to ensure that the performance of the probe is correct.
- After the calibration is done, touch the pointy tip of the probe in the positive terminal of your circuit and ground the ground terminal. If everything goes well and the circuit is functional, you will see a signal on the screen.
- Now, sometimes you won’t see a perfect signal at the first instant. Then you need to trigger the output by the trigger knob.
- You can observe the output the way you want by adjusting the voltage per division and frequency changing knob. They control the vertical gain and time base.
- To observe more than one signal together, connect another probe keeping the first one still connected. Now select the two channels simultaneously. There you go.
Once a few measurements have been made, it becomes much easier to operate an oscilloscope. As oscilloscopes are one of the mainstay pieces of equipment, it is important for anyone involved in electronics to know how to use an oscilloscope and how to make the best use of them.