Compensating BNC Oscilloscope Probes

write an overview, add a picture of some BNC probes

• A probe to be compensated
• An oscilloscope with a BNC connectors and appropriate BNC oscilloscope probes:
  • Analog Discovery Pro (ADP5250)
  • Analog Discovery Pro (ADP3450/3250)
  • Analog Discovery Pro (ADP2230)
  • Analog Discovery 3 or Analog Discovery 2 with the BNC Adapter
• A square wave source:
• Analog Discovery Pro (ADP5250) features dedicated Probe Compensation tabs
• For other devices, the built-in Arbitrary Waveform Generator can be used to produce 5 kHz square waves

This guide is broken up into sections for each type of device that might require probe compensation. Open the dropdown corresponding to your device to view the required steps:

Analog Discovery Pro 2000 Series (ADP2230)

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Analog Discovery Pro 3000 Series (ADP3450/ADP3250)

Connect the probe to the BNC input of the oscilloscope and set the probe to its 1x attenuation setting. Connect the probe tip directly to the source of the square wave and connect the grounding tip to an associated ground point. INFO: The reason you want to connect directly to the source, as opposed to through another probe, is that we want to calibrate the probes with an accurate signal source. Probes themselves, both passive and active, have additional internal circuitry which can distort the square wave, causing the probes to be incorrectly calibrated.

<ADP3450_connectProbe.jpg>

If using one of the Analog Discovery Pro 3000 series with no other source of a square wave, attach a BNC minigrabber (or similar) to a Wavegen output and connect the positive end to the probe tip and the ground end to the probe ground clip.

<ADP3450_connectSquare.jpg>

Open the Scope tool in the WaveForms software. Enable the appropriate channel corresponding to what your probe is attached to (probably channel 1) and set the time division to 200 us/div.

If connected to a square wave from a Waveform Generator on a Discovery device, set the time base to 200 us/div and leave the offset and range at their default values.

<AD2_ScopeSetup.png>

Then open the Wavegen tool and configure the output to be a 1 kHz Square wave with an amplitude of 1 V.

<AD2_WavegenSetup>

- use a screwdriver to adjust your probe's compensation capacitor until the square wave visible in the Scope plot looks appropriately square.

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Analog Discovery Pro 5000 Series (ADP5250)

Connect the probe to the BNC input of the oscilloscope and set the probe to its 1x attenuation setting. Connect the probe tip directly to the source of the square wave and connect the grounding tip to an associated ground point. INFO: The reason you want to connect directly to the source, as opposed to through another probe, is that we want to calibrate the probes with an accurate signal source. Probes themselves, both passive and active, have additional internal circuitry which can distort the square wave, causing the probes to be incorrectly calibrated.

<ADP5250_connectProbe.jpg>

If connecting to the ADP5250's probe compensation tabs, connect the probe to the top tab with the square wave symbol, and the probe ground clip to the lower connector with the ground symbol.

<ADP5250_connectTabs.jpg>

<AD2ADP_connectTabs.jpg>

Open the Scope tool in the WaveForms software. Enable the appropriate channel corresponding to what your probe is attached to (probably channel 1) and set the time division to 200 us/div. Adjust the offset to -1 V and the range to 1 V/div

<AD2APD_ScopeSetup.png>

- use a screwdriver to adjust your probe's compensation capacitor until the square wave visible in the Scope plot looks appropriately square.

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Analog Discovery 3 or Analog Discovery 2 with BNC Adapter

Connect the probe to the BNC input of the oscilloscope and set the probe to its 1x attenuation setting. Connect the probe tip directly to the source of the square wave and connect the grounding tip to an associated ground point. INFO: The reason you want to connect directly to the source, as opposed to through another probe, is that we want to calibrate the probes with an accurate signal source. Probes themselves, both passive and active, have additional internal circuitry which can distort the square wave, causing the probes to be incorrectly calibrated.

<AD2BNC_connectProbe.jpg>

For the Analog Discovery 3 or Analog Discovery 2, connect to the Waveform generator pin directly.

<AD2BNC_connectSquare image>

If connected to a square wave from a Waveform Generator on a Discovery device, set the time base to 200 us/div and leave the offset and range at their default values.

<AD2_ScopeSetup.png>

Then open the Wavegen tool and configure the output to be a 1 kHz Square wave with an amplitude of 1 V.

<AD2_WavegenSetup>

- use a screwdriver to adjust your probe's compensation capacitor until the square wave visible in the Scope plot looks appropriately square.

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You can find more information about your Mixed-Signal Oscilloscope through its resource center, which can be found via the Test and Measurement page of this site.

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