1、BRITISH STANDARD BS 448-2:1981 Incorporating Amendment No. 1 Dimensions of electronic tubes and valves Part 2: Specification for dimensions of United Kingdom electronic tubes UDC 621.38 181BS448-2:1981 This British Standard, having been prepared under the directionof the Electronic Components Standa
2、rds Committee, was published underthe authority of the Executive Board and comes intoeffect on 31July1981 BSI 01-2000 First published (as BS448) May1932 First revision March1936 Second revision August1947 Third revision December1953 Fourth revision (as BS448-2) July1981 The following BSI references
3、relate to the work on this standard: Committee reference ECL/5 Draft for comment79/24466DC ISBN 0580120740 Cooperating organizations The Electronic Components Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following: British Electr
4、ical and Allied Manufacturers Association (BEAMA) Electricity Supply Industry in England and Wales Electronic Components Industry Federation* Electronic Engineering Association Institution of Electronic and Radio Engineers* Ministry of Defence* National Supervising Inspectorate* Post Office Society
5、of British Aerospace Companies Limited Telecommunication Engineering and Manufacturing Association (TEMA) The organizations marked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the preparation of this British Stan
6、dard: Scientific Instrument Manufacturers Association Services Electronic Parts Committee United Kingdom Atomic Energy Authority Amendments issued since publication Amd. No. Date of issue Comments 5999 September 1992 Indicated by a sideline in the marginBS448-2:1981 BSI 01-2000 i Contents Page Coope
7、rating organizations Inside front cover Foreword iii Section 1. General 1 Scope 1 2 References 1 3 Definitions 1 4 Drawings and dimensions 1 5 Pin (or contact) numbering 2 6 Pin soldering 2 7 Resilient pins 2 8 Tolerances on pin position 3 9 Gauging 3 10 Gauges and pin straightening tools 3 11 Funct
8、ion of spigot and key 4 Section 2. Drawings and dimensions of electronic tube caps CT4 5 CT5 6 CT6 (screw type) 7 CT9 8 Section 3. Drawings and dimensions of electronic tube reference linegaugesforCRTs RL1 9 Section 4. Drawings and dimensions of electronic tube bases B2D/1.1 (base) 11 B3G/1.1 (base)
9、 12 B3G/2.1 (outline, without top cap) 13 B4A/1.1 (base) 14 B4A/1.2 (base pin and wafer slot position gauge) 15 B4B/1.1 (base) 16 B5/1.1 (base) 17 B5/1.2 (base pin position gauge) 18 B5A/1.1 (base) 19 B7/1.1 (base) 20 B7/1.2 (base pin position gauge) 21 B7D/1.1 (base) 22 B7G/F/1.1 (base) 23 B7G/F/2.
10、1 (tube outline, without top cap) 24 B8F/1.1 (base) 25 B8F/1.2 (base pin and spigot position gauge) 26 B8F/1.5 (base contact ring gauge) 27 B8F/1.6a (base contact spigot gauge I) 29 B8F/1.6b (base contact spigot gauge II) 30 B8-MO/1.1 (Mazda octal base) 31 B8-MO/1.2 (Mazda octal base pin and spigot
11、position gauge) 32 B9/1.1 (base) 33 B9/1.2 (base pin position gauge) 34 B9A/D/1.1 (base) 35BS448-2:1981 ii BSI 01-2000 Page B9A/D/1.2 (pin and tubulation gauge) 36 B9A/D/1.3 (pin straightening tool) 37 B9A/F/1.1 (base) 38 B9A/F/2.1 (tube outline, without top cap) 39 B12E/1.1 (base) 40 B12F/1.1 (base
12、) 41 B12F/1.2 (base pin position gauge) 42 B12J/1.1 (base) 43 B12J/1.2 (base pin position gauge) 44 B14B/1.1 (base) 45 B14B/1.2 (base pin position gauge) 46 B14E/1.1 (base) 47 B14E/1.2 (pin and tubulation position gauge) 48 B14E/1.3 (pin straightening tool) 49 B15B/1.1 (base) 50 B15B/1.2 (base pin p
13、osition gauge) 51 B19A/1.1 (base) 52 B19A/1.2 (base pin position gauge) 53 B23A/1.1 (base) 54 B23A/1.2 (base pin position gauge) 55 B24A/1.1 (base) 56 B24A/1.2 (base pin and spigot position gauge) 57 B26A/1.1 (base) 58 B26A/1.2 (base pin position gauge) 59 B26A/1.3 (pin straightening tool) 60 Append
14、ix A United Kingdom coded caps 61 Appendix B United Kingdom coded reference line gauges for CRTs 61 Appendix C United Kingdom coded bases 62 Publications referred to Inside back coverBS448-2:1981 BSI 01-2000 iii Foreword This revision of this British Standard has been prepared under the direction of
15、 the Electronic Components Standards Committee and comprises two Parts. BS448-1:1981 specifies IEC 1)dimensions of electronic tubes and valves; this Part of BS448 specifies dimensions of electronic tubes registered in the United Kingdom and not covered in Part1. These two Parts together complete the
16、 revision of BS448:1953, which is hereby withdrawn. As international work proceeds, it is anticipated that the data sheets given in this Part of this standard will gradually either be transferred to Part1 or else withdrawn, and that this Part will itself eventually be withdrawn. This Part comprises
17、four sections. Section1 gives general requirements and information applicable to all types of electronic tube base, gauge, etc. Sections2 to4 contain data sheets giving drawings and dimensions of electronic tube caps, reference line gauges and bases, respectively. Sections2 to4 should be read in con
18、junction with section1. The system of classifying electronic tube components is as follows. Caps and reference line gauges are designated “CT” and “RL”, respectively. They are further subdivided into particular types by use of numerals, e.g. “CT4”. Bases are designated “B”, followed by a numeral ind
19、icating the number of pins per base, e.g.“B7” for a7pin base. Different types of bases with a given number of pins are identified by letter suffixes, e.g. “B7D” or “B7G/F” for7 pin bases types D or G/F. An additional numerical suffix is used to convey the following information: /1.1 Base /1.2 Base p
20、in (and spigot, wafer slot or tubulation) position gauge /1.3 Pin straightening tool /1.5 Base contact ring gauge /1.6 Base contact spigot gauge /2.1 Tube outline, without top cap Alternative forms of particular items are distinguished from each other by the suffixes “a” and “b”, e.g. “B8F/1.6a”. A
21、British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a
22、front cover, an inside front cover, pages i to iv, pages1to 62, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) International Electrotechni
23、cal Commission.iv blankBS448-2:1981 BSI 01-2000 1 Section 1. General 1 Scope This Part of this British Standard covers such physical requirements of the bases, caps and outlines of electronic tubes as are necessary to ensure mechanical compatibility and satisfactory electrical contact. Associated ga
24、uges and pin straightening tools are also covered. This standard deals only with electronic tubes registered in the United Kingdom and not covered in BS448-1. Owing to the many variables involved, including tolerances on pin diameters and permissible pitch circle eccentricity, it is not practical or
25、 economical to ensure complete compatibility in isolated cases where many component parts are on extreme opposing limits. The standard is divided into four sections. Section1 specifies general requirements for bases and associated gauges and pin straightening tools. Sections2,3 and4 contain data she
26、ets specifying the dimensions of caps, bases, outlines and associated gauges and pin straightening tools. Appendix A, Appendix B and Appendix C identify which Part of BS448 deals with which particular component. 2 References The titles of the publications referred to in this standard are listed on t
27、he inside back cover. 3 Definitions For the purposes of this British Standard the following definitions apply. 3.1 base that portion of an electronic tube which carries the majority of the pins or contacts used for connection between the electrodes and the external circuit NOTEOne or more isolated c
28、onnectors are sometimes fitted remote from the main group of pins or side contacts. It is not usual to regard these as forming part of the base (see3.3). 3.2 spigot a projection from the base extending beyond the pins and, in cooperation with a hole or recess in the tube socket, providing an axis of
29、 rotation to facilitate the insertion of the tube. The spigot may carry a longitudinal key to ensure the desired orientation of the tube in its holder 3.3 cap an external fitting on an electronic tube distinct from the base and serving as an electrical connection 3.4 seated height the overall height
30、 from the seating plane of the base, including any protrusion such as a tip or top cap 3.5 datum line a radial line used as a reference for numbering base pins or contacts 4 Drawings and dimensions The drawings in this standard are not to scale. Linear dimensions are stated in inches and millimetres
31、; in each case the original system is indicated. The drawings and the inch/millimetre conversions and roundings are aligned with current IEC practice. Third angle projection is used on all drawings. The limits for acceptance are those given in the original system. The limits shown in a derived syste
32、m are calculated from those in the original system and rounded appropriately within the true calculated limits. Thus the tolerances in a derived system may be narrower than those in the original system. In case of disagreement arising from a difference between gauges the article shall be accepted if
33、 it passes any gauge which is made within the tolerances defined in the original system.BS448-2:1981 2 BSI 01-2000 5 Pin (or contact) numbering Pin positions are numbered in succession in a clockwise direction from the datum line beginning with the first pin position, the centre of which is past the
34、 datum line as viewed from the free end of the pins. Each pin is identified by the number of its position. When a contact pin is located in the centre of the base, this may either be numbered or designated as the centre pin. If numbered, it is the highest numbered pin. When there is a short or index
35、 pin, that pin is not to be counted in the numbering of the pins. When a base has concentric pin circles of decreasing diameters, the pin positions on the pin circles are numbered sequentially, continuing from the highest numbered pin position in the outer circle, always numbering in a clockwise dir
36、ection along a decreasing spiral. The datum line is the reference used for the outer pin circle only. 6 Pin soldering Where applicable, the soldering of the connecting wire to the pin shall be so finished that the free end of the pin is smooth. With pins other than resilient pins (see clause7), any
37、increase in pin diameter due to solder shall not exceed0.010 in (0.254mm) and the solder shall not extend more than0.120 in (3.048mm) up from the free end of the finished pin. 7 Resilient pins Maximum and minimum diameters of resilient pins are not defined, but the dimensions of gauges for ensuring
38、adequate resilience of the pins are specified below. 7.1 Dimensions of resilient pins 7.1.1 The length of the pins, measured from the sole of the base and including the collar (if any) and solder, shall be15.5 0.5mm (0.610 0.019in). 7.1.2 The maximum diameter of the pin shall be situated at a point7
39、.5 1.5mm (0.295 0.055in) from its free end. The contour of the sides of the pins shall be convex for the whole distance between the collar and the end of the pin. The curvature shall be least for a distance of3mm (0.118in) on both sides of the position of the maximum diameter. 7.1.3 Pins shall be re
40、silient radially and rigid axially and shall be of such design that after insertion in the minimum gauge they shall require a force of not less than0.5lb (0.226kg) for extraction from the maximum gauge. 7.2 Gauge for resilient pins. The maximum and minimum gauges shall have the dimensions specified
41、in the following table. An example of a convenient form of gauge is shown below. The inch dimensions are derived from the original millimetre dimensions. Ref. Dimensions Inches Millimetres Min. Nom. Max. Min. Nom. Max. Maximum gauge A B C 0.1256 0.315 0.1259 0.65 0.355 0.1259 0.390 3.19 8.00 3.20 16
42、.5 9.00 3.20 10.00 Minimum gauge A B C 0.1231 0.315 0.1231 0.65 0.355 0.1234 0.390 3.125 8.00 3.125 16.5 9.00 3.135 10.00 Gauge for resilient pinsBS448-2:1981 BSI 01-2000 3 8 Tolerances on pin position 8.1 Geometrical tolerances. Geometrical tolerances have been used in this standard to specify vari
43、ations in the positions of the contact pins in bases and permissible variations in the position, concentricity or squareness of gauge features. The methods of expression used are similar to those recommended in BS308. 8.2 Maximum material condition (MMC). The use of the term “Maximum material condit
44、ion” (MMC) in the notes means that the positional tolerances of the pins are specified in relation to their maximum material limits of size. In other words, each group of pins shall be capable of accepting a position gauge which has holes of diameters equal to the maximum material limits of the pins
45、 plus the positional tolerance. If any pin is finished to a size below its maximum material limit this allows it a positional tolerance greater than that specified for its maximum material condition, the increase of positional tolerance being equal to the difference between the specified maximum mat
46、erial limit of size and its actual finished size. 9 Gauging In the section of the standard dealing with individual tube bases the positional requirements are defined, with a few exceptions, by means of gauges. Where gauges are specified, the procedure indicated in the notes accompanying each drawing
47、 refers to the following standard procedures for using gauges. a) Gauging procedure 1. The entire length of the pins shall, without undue force, pass into and disengage from the prescribed gauge. b) Gauging procedure 2. The gauge shall be attached to such an accessory weight as will give the total w
48、eight prescribed in the notes accompanying each gauge drawing. The entire length of the pins shall pass into the gauge and, on withdrawal, shall become disengaged without lifting the total weight of the assembled gauge and accessory weight. Solder shall be removed from the sides of the pins prior to
49、 gauging. NOTEBefore inserting tubes in equipment or before gauging, bent pins should be straightened by using the pin straightening tool described in the appropriate data sheet. 10 Gauges and pin straightening tools 10.1 Tolerances. The dimensions specified for these items do not define manufacturing tolerances but are limiting dimensions which shall not be exceeded throughout the working life of the item. 10.2 Construction. The relevant drawings in this standard show, in general, only the essential features of the gauges and pin straightening tools. T
