OD1402 - Lesson 1/Learning Event 1
chassis ground of the equipment under test. This completes the
ground connection between the equipment under test and the
oscilloscope. The probe ground strap must always be connected when
measuring signals.
Attenuation Factor
A probe may have an attenuation factor of ten (10) or one hundred
(100). The signal amplitude is reduced by the attenuation factor
of the probe. This is done to allow for the measurement of signal
amplitudes that exceed the rated input of the vertical amplifier.
Voltage Calculation with Probe Attenuation
When using a probe that has attenuation, an additional step must be
added to the procedure for computing the voltage.
Signal X VOLTS/DIV X Probe = PeaktoPeak
Amplitude Switch Setting Attenuation Voltage
Probe Calibration
When a probe is used with an oscilloscope for the first time, or
when it is transferred from one plugin unit to another, the probe
must be calibrated. This will ensure accurate attenuation of
signals. Calibrate the probe as follows:
Step 1. Touch the probe tip to the center CALIBRATOR OUTPUT
connector and adjust the oscilloscope to display several cycles of
the signal.
Step 2. Loosen the locking sleeve and turn the probe body tip
assembly until the correct waveform is displayed on the screen
(figure 16, on the next page).
Step 3. After the correct adjustment has been made, hold the probe
body and tighten the locking sleeve. The probe is now ready for
use.
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