Tektronix 502 series, Инструкция по эксплуатации

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OPERATING INSTRUCTIONS
INPUT SELECTION
On the Type 502 Oscilloscope, you can con­
nect single-ended inputs to either the “ A ” or
"B” input connectors of the lower or upper beam
amplifiers by rotating the input selector switches
to the corresponding positions. The choice of
input connections will depend upon the display
desired. Waveforms applied to input “ B” are
displayed in an inverted position on the face of
the crt while waveforms applied to input "A ”
are displayed in the normal upright position. If
you are not aware of this difference in the input
connectors, it is probable that you will im­
properly evaluate the results obtained from an
input to the “ B” connector.
Fig. 3 -1. Inputs to the vertical amplifiers.
Waveforms applied to input connector A are displayed
in the upright position, while waveforms applied to in­
put connector B are inverted.
Differential inputs must be connected to both
the "A ” and “ B” input connectors of one ampli­
fier. In the A and B positions of the input selec­
tor switch, the corresponding waveforms are dis­
played on the crt. In the A-B (DIFF) position, the
“ B" input is algebraically subtracted from the
“ A " input and the difference is displayed. This
feature permits you to eliminate common mode
signals, and to observe a waveform which is
peculiar to one input.
INPUT
t o
A
INPUT
TO B
liil muml
DISPLAYED
WAVEFORM
Fig. 3 -2 . Rejection of a common mode signal by the
differential amplifier.
The waveform applied to input connector B is alge­
braically subtracted from the waveform applied to in­
put connector A and the difference waveform is dis­
played on the screen of the crt.
INPUT COUPLING
Input signals to the vertical amplifiers can be
either ac or dc coupled by placing the input
selector switch in the corresponding positions.
DC coupling applies both the ac and dc com­
ponents of the input signal to the vertical ampli­
fier circuits. This permits you to measure the dc
voltage level as well as the amplitude of the ac
component. It is sometimes neither necessary
nor desirable to display the dc component how­
ever, and in such cases ac coupling should be
used. With ac coupling, a capacitor is placed
in series with the input connector to block the
dc component while at the same time allowing
the ac component to be displayed.
®
OPERATING INSTRUCTIONS — TYPE 502
3-1