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test-and-measurement:guides:probe-compensation [2024/02/28 22:01] – [Inventory] Arthur Browntest-and-measurement:guides:probe-compensation [2024/02/28 22:36] – added irl trimmer adjustment James Colvin
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 ===== Overview ===== ===== Overview =====
  
-BNC connectors are a commonly used interface for analog inputs on many oscilloscopes, offering both the ability to read higher voltages than oscilloscope natively supports as well as higher bandwidth to provide users better insight into the high speed signals they are observing with much more accuracy than is offered by MTE or coax cables. However, as the 10x mode of the BNC probe adds extra resistance to correspondingly attenuate the input signal down by a factor of 10, the capacitance of the BNC probe is not likely to match the capacitance of the analog input channel you are using, resulting in the measured signal to be over- or under-compensated rather than accurately showing the signal you are viewing. Luckily, this can be mitigated by adjusting the capacitance of the BNC probe. +BNC oscilloscope probes are commonly used for analog inputs on many oscilloscopes, offering both the ability to read higher voltages than an oscilloscope natively supports as well as higher bandwidth, providing users better insight into the high-speed signals they are observing with much more accuracy than what is offered by MTE cables. However, as the 10x mode of the BNC probe adds extra resistance to correspondingly attenuate the input signal down by a factor of 10, the capacitance of the BNC probe is not likely to match the capacitance of the analog input channel you are using, resulting in the measured signal to be over- or under-compensated rather than accurately showing the signal you are viewing. Luckily, this can be mitigated by adjusting the capacitance of the BNC probe. 
  
 This guide walks through how to make this adjustment for Digilent's Test and Measurement devices.  This guide walks through how to make this adjustment for Digilent's Test and Measurement devices. 
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-<columns 100% 50% 50%> + 
-Use a small flathead screwdriver (a small plastic one is typically included with BNC probes) to adjust your probe's compensation capacitor until the square wave visible in the Scope plot looks appropriately square. The probe trimmer is often located on the BNC connector end of the probe. +Use a small flathead screwdriver (a small plastic one is typically included with BNC probes) to adjust your probe's compensation capacitor until the square wave visible in the Scope plot looks appropriately square. The probe trimmer is often located on the BNC connector end of the probe as shown in {{ref>PhysicalAdjustProbeTrimmer}}.
  
 A small video showing an example of adjusting an overcompensated probe to instead be a flat square wave can be found in {{ref>AdjustProbeTrimmerUntilSquare}}. A small video showing an example of adjusting an overcompensated probe to instead be a flat square wave can be found in {{ref>AdjustProbeTrimmerUntilSquare}}.
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 +<columns 100% 50% 50%>
 +<figure center|PhysicalAdjustProbeTrimmer>
 +{{test-and-measurement:guides:physicalprobetrimmeradjustment.png?500|I unironically love this screwdriver. The phillips and flat head ends are actually useful sizes.}}
 +<caption>//Use a flat head screwdriver to adjust the BNC probe trimmer.//</caption>
 +</figure>
  
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