Operation with teledyne lecroy oscilloscopes, Ap033 active differential probe – Teledyne LeCroy AP033 User Manual
Page 18
AP033 Active Differential Probe
12
922260-00 Rev A
Table 1, AP033 Dynamic ranges and input capacitance at different attenuator settings
÷1 Attenuation
÷10 Attenuation
÷100 Attenuation
Common Mode Range
•±4.2 V
•±42 V •
±42 V
Differential Mode Range with
x1 Gain*
•±400 mV •
±4 V •
±40 V
Differential Mode Range with
x10 Gain*
•±40 mV •
±400 mV •
±4 V
Input Capacitance, each side to Ground
6.0 pF
3.0 pF
1.9 pF
Input Capacitance each side to Ground
with AC Coupler
7.3 pF
4.3 pF
3.2 pF
*Offset moves the center point of this range.
When you are using a differential probe or amplifier, be careful not to exceed the common mode
range. Because the common mode signal is rejected by the probe, and not displayed, changes in
the amplitude of the common mode component are not apparent. Exceeding the common mode
range may introduce distortion into the AP033 output. To reduce the possibility of errors caused by
exceeding the common mode range, the probe monitors the input voltage. If the common mode
range is exceeded when the
÷
input attenuator is selected, the probe will automatically switch to
the
÷
attenuator. If the voltage on either input exceeds 55 volts, both the
÷
and
÷
attenuator lights will alternately flash to alert the user to the over-range condition. There are
two combinations which result in x1 effective gain. A
÷
attenuation with x10 gain results in
higher common mode range and lower input capacitance, but it increases the noise referred to the
input. Conversely,
÷
attenuation with x1 gain reduces the noise at the expense of less common
mode range and greater input capacitance.
Circuitry in the probe decodes the effective gain of the probe based on the settings of the gain,
internal attenuation and the presence of the external attenuator. The resulting effective gain is
displayed on the probe front panel.
Operation with Teledyne LeCroy Oscilloscopes
When the AP033 probe is connected to a Teledyne LeCroy oscilloscope equipped with the ProBus
interface, the displayed scale factor and measurement values will be adjusted to account for the
effective gain of the probe.
When the AP033 probe is first connected to the oscilloscope, the following message will appear:
“WARNING: Probe offset buttons are locked”. This is to alert the user that offset control must be
made through the oscilloscope, rather than through the buttons located on the probe. It does not
indicate a failure in the probe or oscilloscope.