Hardware Installation; Power The Instrument; External Power - TiePie Handyscope HS3 User Manual

Hardware installation

Drivers have to be installed before the Handyscope HS3 is
connected to the computer for the first time. See chapter
for more information.
5.1

Power the instrument

The Handyscope HS3 is powered by the USB, no external power
supply is required. Only connect the Handyscope HS3 to a bus
powered USB port, otherwise it may not get enough power to op-
erate properly.
5.1.1

External power

In certain cases, it can be that the Handyscope HS3 cannot get
enough power from the USB port.
When a Handyscope HS3 is connected to a USB port, the hard-
ware will be powered, resulting in an inrush current, which is higher
than the nominal current. After the inrush current, the current will
stabilize at the nominal current.
USB ports have a maximum limit for both the inrush current
peak and the nominal current. When either of them is exceeded,
the USB port will be switched off. As a result, the connection to
the Handyscope HS3 will be lost.
Most USB ports can supply enough current for the Handyscope
HS3 to work without an external power supply, but this is not
always the case. Some (battery operated) portable computers or
(bus powered) USB hubs do not supply enough current. The exact
value at which the power is switched off, varies per USB controller,
so it is possible that the Handyscope HS3 functions properly on
one computer, but does not on another.
In order to power the Handyscope HS3 externally, an external
power input is provided for. It is located at the rear of the Handy-
Hardware installation
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