Getting Started; Overrange Indicator - Cal Test CT3681 User Manual

3.3 Getting Started

1. Connect the hook probes to the leads.
2. Connect the probe to the oscilloscope with the BNC cable.
When using a portable or ungrounded oscilloscope, connect
the output ground lead to ground.
3. Switch the probe "ON."
4. Switch to the desired attenuation ratio. When measuring
signals below 700 V, switch the attenuation ratio to
100x in order to get higher resolution and less noise
ratio. Otherwise, set the attenuation ratio to 1000x when
measuring signals up to 7000 V.
5. Use the hook probes to contact the circuit to be tested.
CAUTION
This probe is used to carry out differential measurements between
two points on the circuit under test. This probe is not for electrically
insulating the circuit under test and the measuring instrument.

3.4 Overrange Indicator

The overrange indicator lights when the voltage of the input signal
exceeds the linear operating range of the probe. When this happens,
the signal on the probe output may not accurately represent the signal
on the probe input.
3.5 Vertical Scale on Oscilloscope
The actual vertical scale of the oscilloscope is equal to the attenuation
factor multiplied by the range of vertical scale selected on the
oscilloscope. For example, with the CT3681 set on attenuation 100x,
the oscilloscope on 0.5 V/div, the real vertical scale is 100 x 0.5 = 50 V/
div. With the probe on 1000x, the real vertical scale is 100 x 0.5 = 500
V/div. These values apply when the oscilloscope is set to the typical 1
MΩ impedance input. When the oscilloscope is set to 50 Ω input, the
actual vertical scale will be doubled: 100 V/div for the 100x setting and
500 V/div for the 1000x setting. See Table 1.
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