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Oscilloscope. The general
information.
Switching of inputs.
The circuit of the
external device. Calibration.
The analysis of a
spectrum.
Two-coordinate mode
(dynamic characteriograph).
The generator.
Additional adjustment.
The Capacity - meter.
The Voltage -
Frequency Caracteriograph.
Fig. 1.The circuit of the external device. |
There are two division
steps of a voltage on the each channel: on a range from
minus 12,5V to plus 12,5V (complete scope up to 25V), and
from minus to plus 250V (complete 500V). On the screen
panel of the device there are appropriate switches. If
there is no necessity for the measurement of the large
voltage, it is possible not to make the second division
step (R1, R1', inputs 250V). C -meter or VFC modes are activated by the S1. At this modes the measuring resistor is R3'. |
The amplifier A1 serves
for the dynamic characteriograph mode. The possible circuit of
the amplifier is below, in the fig. 2. The
activation of dynamic characteriograph must be made by the dual
switch S2 with position Osc of the switch S1. The measuring resistor thus
becomes R4. The examinee component is connected between
jacks 1 and 2 (inputs 12,5 V).
It is better instead of two switches S1 and S2 to
use the three-push-button switch with the dependent fixing.
As R1 and R1 ' we recommend to
use special high-voltage resistors with the capacity not less
than 0,5 W.
For connection Cx use contact clips, because examinee
condenser cannot be holded by a hand - capacity of your body
influences result of measurement.
The resistance between points of connection R3 ' and R4
should precisely be measured by a digital tester. It is
necessary to specify sizes of R3 ' and R4 in the program, it
should be done accordingly in modes of C- meter and
two-coordinate oscilloscope.
Notice, there is not an output outside of the
right channel output. In practice at work with external objects
the second channel of the generator is not necessary, it is
useful only to demonstrations, when the oscilloscope inputs are
connected to Stereo Mixer.
It is possible not to make the external device
(fig. 1) or to make it partially, if you do not use all modes of
the program. Then make simple replaceable cables for oscilloscope
(with a divider), C - meter and so on.
The calibration
of the oscilloscope on a voltage
should be made after the connection the external device or the
cable with the divider. This operation will take into
account for the program factors of division of entrance voltage,
depending on fact values of dividers resistance.
Submit on both inputs 12,5V a wave of
a known amplitude from a single source (preferably sine wave form
with frequency 500.. 2000 Hz and amplitude 15.. 20V, press the
button Calibre, enter the actual
value of the amplitude in volts, press Enter,
after that the oscilloscope is calibrated on inputs 12,5 V.
Further if necessary make a calibration of the second step. To do this submit on both inputs 250 V a wave
with amplitude 150.. 200V. Set the switches on the screen
panel on 12,5 V. Read the measured values-
on 1-st channel of green color, on 2-nd - red color. Read
the measured amplitude values- on the 1-st channel near the top
of the screen, on the 2-nd channel - near its bottom. Divide the actual value on measured, it
is factors of easing (it should turn out about 20). Write down them by the text editor
(Notepad) to the file CALIBR, 8 and 9 lines accordingly.
The calibration on inputs of jacks 3 and 4 is
necessary in the VFC mode, so it is described in the comments to VFC.
If you have the mainframe of the
Virtual Laboratory, to do the calibration not necessarily, it is
done for you by the manufacturer.
Fig. 2. The possible circuit of the amplifier. On the loading by the resistance 1 kOm the amplitude of the undistorted wave can be 20..25 V.