Tektronix 305 DMM, Инструкция по эксплуатации

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BASIC INSTRUMENT OPERATION
OPERATING CONSIDERATIONS
To ensure optimum measurement accuracy, the following
inform ation should be considered before operating the
instrument.
Signal Connections
Generally, probes offer the most convenient means of
connecting an input signal to the instrum ent Oscilloscope
probes are shielded to prevent pickup o f electrostatic inter­
ference. The supplied 10X probe offers a high input im­
pedance, which minimizes circuit loading and allows the
circuit under test to operate very close to normal conditions
providing accurate measurements. Conversely, it also at­
tenuates the input signal amplitude by a factor o f 10.
Coaxial Cables
Cables used to connect signals to the input connectors
have a considerable effect on the accuracy o f a displayed
waveform. To maintain the original frequency character­
istics o f an applied signal, high quality, low loss coaxial
cable should be used. Also, the cable should be terminated
at both ends in its characteristic impedance. I f this is not
possible, use suitable impedance matching devices.
Grounding
The most reliable signal measurements are made when
the 305 and the u nit under test are connected together by a
common reference (ground) lead in addition to the signal
lead or probe. The ground strap on the probe provides the
best ground. Also, you can connect a ground lead to the
chassis ground connector located on the right side panel
o f the instrument.
Graticule
The graticule is internally marked on the faceplate o f
the c rt to provide accurate measurements w ith o u t parallax.
The graticule is marked w ith eight vertical and ten horizon­
tal major divisions. In addition, each major division is divid­
ed into five minor divisions. The vertical deflection and
horizontal tim ing are calibrated to the graticule, so accurate
measurements can be made directly from the crt.
REV A SEP 1979
305 Operators
15