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INSTRUCTION MANUAL
NOTES AND CAUTIONS
ELECTRICAL SAFETY PRECAUTIONS
This equipment is protected in accordance with IEC Safety Class 1. It has been
designed and tested according to IEC Publication 348, 'Safety Requirements for Electronic
Measuring Apparatus', and has been supplied in a safe condition. The following pre-
cautions must be observed by the user to ensure safe operation and to retain the equip-
ment in a safe condition.
Defects and abnormal stresses
Whenever it is likely that protection has been impaired, for example as a result of
damage caused by severe conditions of transport or storage, the equipment shall be made
inoperative and be secured against any unintended operation.
Removal of covers
Removal of the covers is likely to expose live parts although reasonable precautions
have been taken in the design of the equipment to shield such parts. The equipment
shall be disconnected from the supply before carrying out any adjustment, replacement or
maintenance and repair during which the equipment shall be opened. If any adjustment,
maintenance or repair under voltage is inevitable it shall only be carried out by a
skilled person who is aware of the hazard involved.
Note that capacitors inside the equipment may still be charged when the equipment
has been disconnected from the supply. Before carrying out any work inside the equip-
ment, capacitors connected to high voltage points should be discharged; to discharge
mains filter capacitors, if fitted, short together the L (live) and N (neutral) pins of
the mains plug.
Mains plug
The mains plug shall only be inserted in a socket outlet provided with a protective
earth contacts The protective action shall not be negated by the use of an extension
lead without protective conductor. Any interruption of the protective conductor inside
or outside the equipment is likely to make the equipment dangerous.
Fuses
Note that there is a supply fuse in both the live and neutral wires of the supply
lead. If only one of these fuses should rupture, certain parts of the equipment could
remain at supply potential.
To provide protection against breakdown of the supply lead, its connectors, and
filter where fitted, an external supply fuse (e.g. fitted in the connecting plug) should
be used in the live lead. The fuse should have a continuous rating not exceeding 6 A.
Make sure that only fuses with the required rated current and of the specified type
are used for replacement. The use of mended fuses and the short-circuiting of fuse
holders shall be avoided.
RADIO FREQUENCY INTERFERENCE
This equipment conforms with the requirements of lEC Directive 76/889 as to
limits of r.f. interference.
(2a)
Contents
Section 1 GENERAL I N F O R M A T I O N
1.1 Introduction
1.2 Data s u m m a r y
1.3 Accessories
Section 2 OPERATION
2.,1 Installation
2.,2 Controls and c o n n e c t o r s
2.. 3 Preliminaries 9
2.. 4 Connecting the component 10
2. 5 Resistance measurement 10
2.,6 Inductance m e a s u r e m e n t 12
2..7 Notes on inductlve l o s s balancing 16
2.8 Using the D. C. Choke Adaptor Type TM 6113 17
2.9 Capacitance m e a s u r e m e n t 18
2.10 Notes on capacitive l o s s balancing 21
2.11 Use of e x t e r n a l o s c i l l a t o r and d e t e c t o r 21
Section 3 T E C H N I C A L DESCRIPTION
3.1 Circuit s u m m a r y 23
3.2 M e a s u r i n g b r i d g e a. c. supply 24
3.3 M e a s u r i n g b r i d g e d. c. supply 24
3.4 M e a s u r i n g bridge c i r c u i t s 24
3.5 Amplifier d e t e c t o r 25
3.6 P o w e r supplies 26
3.7 D. C. Choke A d a p t o r Type TM 6113 26
Section 4 MAINTENANCE
4.1 General 28
4. 2 Removal from c a s e 28
4.3 A c c e s s t o components 28
4.4 Mains input adjustments 28
4.5 Working v o l t a g e s 28
4.6 R e p l a c e m e n t of valves 31
4. 7 Adjustment of p r e s e t components 31
4.8 Checking the l o s s b a l a n c e diai calibration 36
4. 9 A c c e s s and adjustment to balance control a s s e m b l y 36
Section 5 REPLACEABLE PARTS
Universal bridge 41
D. C. choke adaptor 53
Section 6 C I R C U I T DIAGRAMS
Fig. 6.1 P o w e r supply and o s c i l l a t o r 47
Fig. 6.2 Bridge 49
Fig. 6.3 Detector 51
Fig. 6.4 D. C. choke a d a p t o r 53
1313A (1)
General information
1.1 INTRODUCTION 10kc/s; the detector output is available externally
to allow an oscilloscope or headphones to be used
for balance indication.
TF 1313A is a general-purpose impedance
bridge with one tenth per cent measurement This bridge can be used for precision eval-
accuracy over a wide range of inductance, capac- uation of resistance, capacitance and inductance,
itance, and resistance values. It offers except- for measuring the dissipation factor of capacitors
ional discrimination and resettability, wide-range and Q of inductors, and for quickly identifying
loss balancing, and facilities for using an external unknown components. Measurements on high-loss
oscillator and detector. components are made easier by the low D and Q
ranges of the loss balance control and the relative
The single direct-reading dial used for L, independence between the adjustment of the main
C, and R measurements has coarse aiid fine con- and loss balance controls. Its high discrimination
centric controls; the coarse one moves in 1% and resettability make it particularly suitable for
steps and the fine gives continuously variable comparative measurements such as checking the
interpolation between steps. The variable and difference between an unknown and a standard
non-linear sensitivity of the detector facilitates component. Measurements on inductors carrying
easy measurement of completely unknown comp- d. c. can be made by using Adaptor TypeTM6113,
onents. An external audio oscillator can be which is available as an optional accessory, while
plugged in where L and C measurements are req- an external d. c. supply can be connected direct
uired at frequencies other than the internal 1 and for polarizing capacitors.
Fig. 1.1 0-1% Universal bridge TF 1313A
1313A (la)
General information
1.2 DATA SUMMARY
Resistance measurement
Range 3 m to 110 M. in eight r a n g e s with m a x i m a of 1 1 , 1 1 0 ,
1.1 k, 11 k, 110 k, 1.1 M, 11 M, 110 M.
Accuracy : Basic measurement e r r o r :