HP 400D, Инструкция по эксплуатации и обслуживанию

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1-1
GENERAL DESCRIPTION
This vacuum tube voltmeter is an accurate and
sensitive average-responding rms calibrated volt­
meter which will measure ac voltages from 0.001
volt full scale to 300 volts full scale over a fre­
quency range of
10
cycles to 4 megacycles.
It
has
an input impedance of 10 megohms, effectively
preventing disturbance to circuits under test. The
distinctive features
of
this voltmeter make it valuable
for measuring gain, network response, and output
level with speed
and
accuracy. The wide frequency
range makes it suitable for audio, ri, and video
measurements.
TABLE 1-1. RANGES
Switch Position Voltage
Decibel
Volts db Range Range
.001
-60 0
to 0.001 -72 to -58
.003 -50
0 to 0. 003 -62 to
-48
. 01 -40
0 to
0. 01 -52
to
-38
. 03 -30
0 to 0,03
-42
to -28
. I
-20 0 to 0.1 -32 to -18
. 3
-10
0 to 0. 3
-22
to - 8
I 0
0 to
I
-12 to + 2
3
- +10
0
to
3 - 2 to +12
10
+20
0 to 10
+
8 to +22
30 +30
0 to 30 +18 to +32
lOO
+40
0 to 100 +28 to +42
300 +50 0 to 300 +38 to +52
The sensitivity
of
the voltmeter is sufficient in many
instances to measure hum and noise level directly.
The voltmeter also may be used as
an
audio level
meter; as a high-gain broadband amplifier to give
increased sensitivity to oscilloscopes, bridges, and
other equipment requiring additional sensitivity;
and to detect nulls.
Sect. I Page 1
SECTION I
GENERAL DESCRIPTION
1-2 DAMAGE IN TRANSIT
If
upon initial inspection this instrument is found
to be damaged in any way, refer to CLAIM FOR
DAMAGE IN SHIPMENT for the necessary in­
structions.
1-3
POWER LINE VOLTAGE
The instrument is normally supplied wired for 115-
volt operation.
If
it is desired to operate the in­
strument from a 230-volt source, refer
to
the trans­
former conversion data on the schematic diagram
for the correct procedure.
Refer to the Table of
Replaceable PartoS
for the
correct power line fuse for 230 -volt operation.
1-4 POWER CABLE
The three conductor power cable supplied with this
instrument is terminated in a polarized three-prong
male connector recommended by the National Elec­
trical Manufacturers' Association. The third con­
tact is an offset round pin, added to a standard two­
blade connector, which grounds the instrument
chassis when used with the appropriate receptacle.
T o use this NEMA connector in a standard two­
contact receptacle, an adapter may be used. The
ground connection emerges from the adapter as a
short lead which should be connected to a suitable
ground for the protection of operating personnel.
1-5 ACCESSORIES
Accessories available for use with the Mo:IeI400D/lI/L
Vacuum Tube Voltmeter are listed below. These
accessories are not supplied with the instrument
but may be purchased from the Hewlett-Packard
Company.