Fnirsi DPOX180H Instruction Manual page 5

Warning
●When the two channels are used at the same time, the ground clips of the two probes
must be connected together. It is strictly forbidden to connect the ground clips of the
two probes to different electric potentials, especially the different potential terminals of
high-power device or 220V. Otherwise, the main board of the oscilloscope will be
burned, because the two channels are common ground, and connecting to different
potentials will cause a short circuit of the internal ground wire of the main board, which
isthe case for all oscilloscopes.
●The oscilloscope's BNC terminal input can tolerate up to 400V, and it is strictly forbidden
to input more than 400Vvoltage under the 1Xprobe switch.
●Charging must be charged with a separate charger. It is strictly forbidden to use the
power supply or USB of other currently tested devices, otherwise it may cause a short
circuit to the ground wire of the mainboard during the test and burn the mainboard.
●When measuring high-frequency and high-voltage signals, you must use 100Xprobes
(such as ultrasonic welding machines, ultrasonic cleaning machines, etc.) or even
1000X probes (such as high-voltage ends of high-frequency transformers, induction
cooker resonant coils, etc.)
Notice
The bandwidth of the 1 X probe gear of the accessory probe is 5 MHz, and the
bandwidth of the 10 X probe gear is 200 MHz. When measuring a frequency higher
than 5 MHz, you need to switch the probe to the 10 X gear, and the oscilloscope
should also be set to the 10 X gear. Otherwise the signal will be greatly attenuated,
as is the case with all oscilloscopes. Because the probe line of the oscilloscope itself
has a capacitance as high as 100~300 pF, which is a large capacitance for high-
frequency signals! The signal has been greatly attenuated when it reaches the input
end of the oscilloscope through the probe, and the equivalent bandwidth is 5 MHz.
Therefore, in order to match the hundreds of pF of the probe line, the input end of the
probe line isfirst attenuated by 10 times (the switch is at 10 X), so that hundredsof pF
capacitors are just used for impedance matching. At this time, the bandwidth is 200
MHz. Note that only probes with a bandwidth of 200 MHz or above can be used.
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