Complete Guide How to calibrate DSO 138 Oscilloscope

foreign hello and welcome back and if you are new here welcome we are very glad to have you here in this video we will demonstrate how to calibrate the DSO 138 oscilloscope so let's get started the calibration is process or method aimed to ensure that the device is working correctly and providing accurate measurements it is important to calibrate your oscilloscope so that you are confident that your measurements are valid in real life calibration is process of comparing measurements between established known value against values of the device you are calibrating in case of our oscilloscope calibration is process of adjusting two variable capacitors Mark C4 and C6 in order to get clean signal displayed on screen here is an example of Ideal Square signal notice that the edges of signal are sharp horizontal and vertical lines are straight and there is no deformation in shape of signal the aim of calibration is to get our oscilloscope signal as close as possible to this ideal Square signal there are three scenarios that we can encounter when we start to calibrate our oscilloscope first one is that our oscilloscope is already tuned up and that signal we see on display is perfect square signal like one on the photo second scenario is that edges of our Square signal are rounded obviously this is unwanted Distortion of the signal that we want to rectify through the calibration process foreign third scenario is that edges of our Square signal are spiked this too is unwanted Distortion that needs to be rectified via calibration process [Music] before we begin with demonstration it is important to point out the quality of power source for this particular example we will be using nine volt battery the reason for this is that we want to eliminate all possible sources of interference cheap AC DC adapters can introduce a fair amount of electrical interference and unduly influence our calibration process battery is reliable steady and interference-free source of power so it is The Logical choice next important piece of business is our signal source the DSO 138 has built-in Square signal generator that we will be using as signal source at this point you could ask can we not use signal from external source no we are calibrating the device not the signal here a signal is visual representation of adjustment of the device's internal electrical components aimed to achieve the best looking and interference free signal and last piece of advice it is best to finish calibration process before you enclose the oscilloscope in acrylic case when enclosed in its protective acrylic case access to Signal generator port in C4 and C6 capacitors is obstructed in order to recalibrate device you would have to dismantle entire acrylic case let's assemble our workbench connect the probe cable to BNC connector at the back of the oscilloscope locate signal generator connection point and use red alligator clip to attach probe cable to it leave black alligator clip unattached connect the battery to power up the oscilloscope set CPL switch to either AC or DC position set scn1 switch to 0.1 volt position and set sen2 switch to X5 position adjust time base to 0.2 milliseconds or 200 microseconds depending of type of oscilloscope you have if necessary use vertical position indicator to Center signal on display if you have followed these steps you should see signal on your display now take two millimeter flathead screwdriver and gently insert it into opening a bottom C4 capacitor pay close attention to a line screwdriver with grooves on top of the capacitor very slowly turn screwdriver left or right in order to adjust shape of the signal so that you have edges of the signal as Square as possible if necessary you can use magnifying glass to see signal more clearly [Music] thank you [Music] when done remove screwdriver set scn1 switch to one volt position and set scn2 switch to X1 position repeat the same process with top C6 capacitor turning screwdriver left or right adjust the shape of signal so that you have edges of the signal as Square as possible when you are satisfied with how your signal looks the calibration process is complete now you can detach battery and after that remove red clip from board you can now use your oscilloscope with any other external signal source and be assured that you will have the best possible display of input signal please before you leave show your appreciation by liking this video sharing it leaving a comment and consider subscribing thank you and see you next time bye [Music]

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Views: 5,694

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Id: BZw4RFVwzw4

Length: 6min 46sec (406 seconds)

Published: Thu Jun 22 2023