General - Tektronix CURVE-TRACER 576 Instruction Manual

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Type 576
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SECTION 5
1
\.tp£RFORMANCE CHECK/CALIBRATION
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Change information, if any, affecting this section will be found at the rear of the manual.
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GENERAL
Introduction
The Type 576 should be checked and, if necessary, recal-
ibrated after each 1000 hours of operation or at least once
every six months, to ensure that it is operating properly. In
addition, portions of the instrument may require recali-
bration if components are replaced or other electrical re-
pairs are made. This procedure provides instructions for
adjusting the Type 576 internal adjustments and checking
the performance of the Type 576 against the electrical
characteristics listed in Section 1.
NOTE
An alternate method of calibrating the Type 576 is
available which uses a special Type 576 Calibration
Fixture (Tektronix Part No. 067 -0599-00). This fixture
provides a more efficient method of calibrating the
Type 576. The fixture is particularly useful when sev-
eral Type 576's are to be calibrated. A performance
check/calibration procedure using this fixture is in-
cluded at the end of this section as appendix A.
Maintenance
Any maintenance required on the Type 576 should be
completed before starting this procedure. If instrument
troubles occur while using this procedure, they should be
corrected before proceeding. Repair and servicing infor-
mation is given in the Maintenance section.
Equipment List
The following equipment list shows the required test
equipment ranges and tolerances and suggests particular test
instruments. For accurate measurement, the tolerances re-
quired for each piece of test equipment must exceed the
measured tolerance by at least 4 times. For measured toler-
ances of less than 1%, the accuracy of the test equipment
must exceed that tolerance by at least 10 times.
1. DC Voltmeter-Requirements: range of 0 to ± 1000
V, basic accuracy of ±0.5%, accuracy of 0.05% ± 1 mV
· etween 0 and ±75 volts, input impedance of at least 500
&"2.
Fluke Model 801 B differential voltmeter suggested. A
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digital voltmeter can be used if its input impedance is accur-
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REV AUG 1984
ately known. If the meter chosen has an input impedance
of less than 500 MQ, the voltages measured in steps 19 and
24 will not coincide with those shown in Tables 5-9 and
5-11. Instructions for calculating the proper voltages are
given in those steps.
2. DC Voltmeter (High Voltage)-Requirements:
Measure -4000 volts, accuracy within 3% (Triplett Model
630 NA suggested).
3. Test Oscilloscope-Requirements: 200 kHz bandwidth
sweep rates from 5 ms/cm to 5 [J.S/cm, vertical deflection
factors from 10 mV/div to 2 V/div, accuracy of voltage
measurement within 3%, AC and DC coupling, internal
triggering, 1 X probe included. A Tektronix Type 422, Type
453, or Type 561 B/2A63/2867 is suggested.
4. Variable Autotransformer (e.g., General Radio, Variac
Type W10MT3W for 115-volt operation, or Type
W20HMT3A for 230-volt operation). Minimum Require-
ments: Output voltage variable from 90 V to 136 VAC
RMS for 115-volt operation or from 180 V to 272 VAC
RMS for 230-volt operation; power output of at least 305
watts. If a monitor voltmeter is not included, a separate AC
voltmeter is required.
5. DC Ammeter or Shunt Resistors-The DC voltmeter
(Item 1) and a group of shunt resistors (see Table 5-1) are
used to measure the accuracy of the collector current por-
tion of the VERTICAL switch and the current portion of
the AMPLITUDE switch. The more convenient but more
expensive method of checking these switches is to use a DC
ammeter with the following range and accuracy: range from
50 [.LA to 10 A, accuracy within 0.5%. If such an ammeter
is available the first 7 resistors in Table 5-1 are not needed.
6. 10 Amp Supply-To measure the 1 A and 2 A posi-
tions of the VERTICAL switch. Requirements: 10 Amps
±0.5%. A DC ammeter is required to check the accuracy of
the supply.
7. Shunt Resistors-The DC voltmeter (Item 1) and a
group of shunt resistors ranging from 25 k&t to 25 MQ (see
Table 5-1) are used to measure the accuracy of the emitter
current portion of the VERTICAL switch.
5-1