HP 400D Operating And Service Manual

T.O. 33A1-12-349-1 Section I
Paragraphs 1-1 to 1-5
SECTION |
GENERAL DESCRIPTION
1-1. INTRODUCTION. (Sce figure 1-1.)
1-2. This manual contains operating and servicing
instructions, anda parts breakdown, for the Models
400D, 400H, and 400L Vacuum Tube Voltmeters manu-
factured by the Hewlett-PackardCompany. The Model
400D Voltmeter is similar toa military counterpart,
Electronic Voltmeter ME-30A/U, in appearance and
operation, but contains modified electrical circuits
to obtain improved performance. Applicable Federal
Stock Numbers for the voltmeters are as follows:
Model 400D: 6625-643-1670
Model 400H: 6625-557-8261
Model 400L: 6625-729-8360
1-3. The Models 400D, 400H, and 400L Voltmeters
are the same except forthe differences listed in Fig-
ure 1-2.
a.
Voltage
Range:
400D/H
-
0.1
millivolt
to
300
volts;
400L
-
0.3
millivolt
to
300
volts,
in
12
ranges
providing
full-scale
readings
of
the
following
voltages:
0.001 0.100 10.00
0.003 0.300 30.00
0.010 1.000 100.00
0.030 3.000 300.00
b. Decibel Range: -72 to +52 db, in 12 ranges.
c, Frequency Range: 10 cps to 4 mc.
d. Input Impedance: 10 megohms shunted by 15 pf
(15 uf) on ranges 1.0 volt to 300 volts; 25 pf on ranges
0.001 volt to 0.3 volt.
e. Stability: Line voltage variations of +10% do not
reduce the specified accuracy, and line voltage transients
are not reflected in the meter reading. Electron tube
deterioration to 75% of normal transconductance affects
accuracy less than 0.5% from 20 cps to 1 mc,
{. Amplifier: OUTPUT terminals are provided so
that the voltmeter can be used to amplify small signals
or to enable monitoring of waveforms under test with
an oscilloscope. Output voltage is approximately 0.15
volt rms on all ranges with full-scale meter deflection.
Amplifier frequency response is same as the voltmeter.
Internal impedance is approximately 50 ohms over
entire frequency range,
a. The front panel meters are different in each
model, as described in paragraph 1-6.
b. The accuracy specifications are different for
each model, as described in figure 1-2.
1-4. DESCRIPTION.
1-5. The Hewlett-Packard Models 400D, 400H, and
400L Vacuum Tube Voltmeters are general purpose,
portable electronic a-c voltmeters of high sensitivity
and stability. They are suited to both laboratory and
field use. Models 400D/H measure a-c voltages from
0. 001 to 300 volts and Model 400L from .003 to 300
volts rms fullscale, witha frequency bandwidth cover-
ing 10cps to4 megacycles. The voltmeters are com-
pact, accurate, and rugged and have fast meter re-
sponse, high input impedance, stable calibration ac-
curacy, and freedom from the effects of normal line
voltage variations. The voltmeters are designed for
long instrument life with a minimum of servicing.
g. Accuracy: Model 400D -
+2% of full scale, 20 cps to 1 me;
+3% of full scale, 20 cps to 2 mc;
+5% of full scale, 10 cps to 4 mc.
Model 400H -
+1% of full scale, 50 cps to 500 ke;
+2% of full scale, 20 cpsto 1 me;
+3% of full scale, 20 cpsto 2 me;
45% of full scale, 10 cpsto 4me.
Model 400L -
+2% of reading or +1% of full scale,
whichever is more accurate,
50 cps to 500 ke.
+3% of reading or +2% of full scale,
whichever is more accurate,
20 cps to 1 mec.
+4% of reading or +3% of full scale,
whichever is more accurate,
20 cps to 2 mc,
+5% of reading 10 cps to 4 mc.
h. Power Requirement: 115/230 volts 410%, 50 to
1000 cps, approximately 100 watts.
i, Size: 11-3/4 in. high, 7-1/2 in, wide, 12 in, deep,
j. Weight:
23 Ibs.
18 lbs; shipping weight approximately
Figure 1-2. Table of Specifications
00102-3
1-1

HP 400D Specifications

General

Brand	HP
Model	400D
Category	Measuring Instruments
Language	English