1162:
elsewhere in the world; notably, in the United States. Production of these lamps continued until the early 1980s, although manufacturers had produced adaptors that permitted bi-pin lamps being used in older luminaires (equipped with bayonet lamp holders) since the 1960s. The BA20d (sometimes called a Bosch fitting) was once a common automotive (twin filament) headlamp fitting but has largely been superseded by more modern, higher-rated H-series sockets and is only used for some lower-powered applications such as combined automotive tail and stop lamps.
151:
310:
T when viewed from the side. The receptacle has two slots resembling curved keyholes which have holes at one end sized to accept the pin ends. The lamp is inserted into the receptacle by placing the pins in the holes and rotating in a clockwise direction. Note that, unlike the traditional bayonet fitting, the retaining springs act laterally on the pins so no inward pressure is required to lock the lamp in the fitting. GU-10 fittings are available in heat-resistant form for use with halogen lamps which generate heat.
365:
376:
384:
140:
132:
124:
27:
354:
339:
259:
pushes the male connector up into the "serif" to keep the pin locked into place. A practised user can connect them quickly and, unlike screw connectors, they are not subject to cross-threading. To disconnect, the two parts are pushed together to move the pin out of the "serif" while twisting in the opposite direction than for connecting, and then pulling apart.
187:(a short upward segment at the end of the horizontal arm); the pin slides into the vertical arm of the L, rotates across the horizontal arm, then is pushed slightly upwards into the short vertical "serif" by the spring; the connector is no longer free to rotate unless pushed down against the spring until the pin is out of the "serif".
1161:
Of these, only the BC (BA22d, often abbreviated as B22) is widely used in homes. Formerly, some linear fluorescent lamps in the UK used BA22d end caps, owing to material shortages arising from the Second World War, which prevented the development of the bi-pin cap design that was becoming commonplace
309:
The GU-10 light fittings in common use for both halogen and LED miniature spotlight lamps have a similar means of connection but the retaining pins are fitted to the end of the lamp and also double as the electrical contacts. The pins are cylindrical but the ends have a larger diameter, resembling a
262:
The strength of the joint comes from the strength of the pins and the L slots, and the spring. To disengage unintentionally, the pins must break, the sleeve into which the connector slides must be distorted or torn enough to free the pins, or the spring must fail and allow the connector to be pushed
273:
are used in the same applications where other connectors are used, to transmit either power or signals. Bayonet connections can be made faster than screw connections, and more securely than push-fit connections; they are more resistant to vibration than both these types. They may be used to connect
472:
from the late 1870s onward, standard bulbs have two pins on opposite sides of the cap; however, some specialized bulbs have three pins (cap designation B22d-3) to prevent use in domestic light fittings. Examples of three-pin bulbs are found in mercury street lamps and fireglow bulbs in some older
496:
Some bulbs may have slightly offset lugs to ensure they can be only inserted in one orientation, for example the 1157 automobile tail-light which has two different filaments to act as both a tail light and a brake light. In this bulb each filament has a different brightness and is connected to a
258:
To couple the two parts, the pin(s) on the male are aligned with the slot(s) on the female and the two pushed together. Once the pins reach the bottom of the slot, one or both parts are rotated so that the pin slides along the horizontal arm of the L until it reaches the "serif". The spring then
504:
Bayonet bases or caps are often abbreviated to BA, often with a number after. The number refers to the diameter of the base (e.g., BA22 is a 22 mm diameter bayonet cap lamp). BA15, a 15 mm base, can also be referred to as SBC standing for small bayonet cap. The lower-case letter
1165:
In Japan, the JIS C 8310 “hook ceiling” bayonet mount is quite common. It is designed to both provide power and carry the weight of a lamp. A similar concept existed in BS 7001 as the slide-in “luminaire-supporting coupler” (LSC), but its prominence is unknown.
182:
consisting of a cylindrical male side with one or more radial pins, and a female receptor with matching L-shaped slot(s) and with spring(s) to keep the two parts locked together. The slots are shaped like a capital letter L with
497:
separate contact on the bottom of the base; the two contacts are symmetrically positioned about the axis of the base, but the pins are offset so that the bulb can only be fitted in the correct orientation. Newer bulbs use a
277:
The coupling system is usually made of two bayonet ramps machined on the external side of the receptacle connector and 2 stainless steel studs mounted inside the plug connector’s coupling nut. Several classes of
477:. Older railway carriages in the UK also made use of a 3 pin bulb base to discourage theft. Bayonet cap bulbs are also very common worldwide in applications where vibration may loosen screw-mount bulbs, such as
501:
which can be inserted either way without complication. Some special-purpose bulbs, such as infra-red, have 3 pins 120 degrees apart to prevent them being used in any but the intended socket.
1186:
to allow lenses to be changed rapidly and locked accurately in position. Camera lens mounts usually employ stronger flattened tabs rather than pins, though their function is the same.
266:
It is possible to push down the connector and rotate it, but not far enough to engage and lock; it will stay in place temporarily, but accidental disconnection is very likely.
1458:
456:). The standard size is B22d-2, often referred to in the context of lighting as simply BC or B22. Older installations in some other countries, including
322:
in the 13th century, who used it to mount candles into his candle-clocks. This type of fitting was later used for soldiers who needed to quickly mount
1448:, 1997. (also: BS EN 61184). Specifies requirements and tests for the B15 and B22 bayonet holders for light bulbs used in some Commonwealth countries
1247:
306:
connectors. (The BNC connector is not exactly as described in this article, as the male, not female, connector has the slots and spring.)
1445:
1355:
530:
514:
1415:
91:
63:
1296:
110:
70:
518:
1483:
77:
48:
44:
1488:
1380:
59:
1189:
A bayonet mount is often used to mate a cylinder with a base in cylindrical packaging such as that for
513:
specifies whether the bulb has single or double contacts. The entries from the table below pertain to
1270:
517:"Lamp caps and holders together with gauges for the control of interchangeability and safety" and to
474:
1190:
465:
357:
1274:
368:
37:
1473:
469:
392:
270:
84:
8:
478:
421:
227:
318:
The first documented use of this type of fitting (without the name "bayonet") may be by
1478:
1344:
371:
with double contact B22d bayonet mount, and corresponding socket with sprung connectors
274:
two cables, or to connect a cable to a connector on the panel of a piece of equipment.
1419:
1179:
398:
163:
150:
1202:
404:
The bayonet light bulb mount is the standard fitting in many former members of the
346:
279:
409:
405:
364:
199:
195:
1323:
1300:
1264:
482:
375:
1467:
1222:
449:
295:
1227:
1212:
490:
445:
303:
1217:
433:
425:
383:
299:
235:
231:
1183:
498:
486:
191:
171:
429:
413:
319:
223:
207:
203:
139:
353:
26:
342:
219:
179:
131:
123:
323:
144:
162:(mainly as a method of mechanical attachment, such as fitting a
1175:
461:
457:
453:
441:
437:
247:
243:
239:
167:
1207:
417:
327:
287:
283:
215:
184:
540:
338:
291:
211:
1416:"Technical Database>Know You Light Bulbs>Lamp Bases"
535:
1266:
397:
For other types of lightbulb mounts and sockets, see
51:. Unsourced material may be challenged and removed.
1418:. The Greenstock Lamp Co Ltd. 2007. Archived from
918:On June 1996, all were withdrawn and replaced by
1465:
294:cables use bayonet connectors. Examples include
198:and in many countries that were members of the
263:down and rotate—for example due to vibration.
1459:Line-voltage Socket Design Competition (GU24)
1321:
1401:DIN 49610:1986-10 , DIN 49612:1984-08 , etc.
1248:"Fiji Electricity Authority Tender Document"
1339:
1337:
135:A bayonet mount before and after insertion
1446:International Electrotechnical Commission
928:These are the available sizes in the UK:
111:Learn how and when to remove this message
382:
374:
363:
352:
337:
149:
138:
130:
122:
1334:
1466:
1375:
1373:
1277:from the original on December 14, 2021
360:with double contact B22d bayonet mount
1324:"The Incandescent Lamp, 1800 to 1900"
895:
379:Preceding bulb mounted in the socket
49:adding citations to reliable sources
20:
1370:
1345:"IEC 60061 - Lamp caps and holders"
468:in the UK and improved upon by the
13:
1438:
1328:Frank's Glass History and Research
1322:Frank Andrews (October 28, 2003).
1142:22 mm double ended (railway)
912:
464:use this base. First developed by
190:The bayonet mount is the standard
14:
1500:
1452:
1036:15 mm, radially offset pins
387:Incandescent 40 W BA15d bulb
1444:IEC 61184: Bayonet lampholders,
1023:15 mm, axially offset pins
982:9 mm, radially offset pins
25:
493:(E) base is used for lighting.
36:needs additional citations for
1407:
1387:. Beuth Verlag GmbH. June 1996
1315:
1289:
1257:
1240:
489:. In many other countries the
333:
1:
1233:
1169:
1044:Single centre contact (SCC)
990:Miniature bayonet cap (MBC)
7:
1196:
1041:BA15s (P21W/1156/R5W/R10W)
10:
1505:
1297:"St. George Lane Fox-Pitt"
1129:22 mm 3 bayonet pins
969:7 mm, elongated pins
432:, as well as parts of the
396:
390:
313:
178:(for electrical use) is a
143:Early-19th century socket
475:electric radiative heater
253:
1381:"DIN EN 60061-1:1996-06"
1004:Small bayonet cap (SBC)
937:Alternative designation
466:St. George Lane Fox-Pitt
358:Compact fluorescent lamp
868:B22d-3(90°/135°)/25x26
448:sockets along with the
444:, which primarily uses
369:Incandescent light bulb
1015:BAY15d (P21/5W, 1157)
470:Brush Electric Company
388:
380:
372:
361:
350:
282:connectors, including
242:and, historically, in
155:
147:
136:
128:
1484:Electrical connectors
1178:with interchangeable
393:Automotive lamp types
386:
378:
367:
356:
341:
326:to the ends of their
271:electrical connectors
153:
142:
134:
126:
1489:Mechanical standards
1422:on February 21, 2009
1303:on November 21, 2013
45:improve this article
806:BA15d-3(100°/130°)
794:BA15s-3(100°/130°)
560:B8.4d & BX8.4d
479:automotive lighting
180:fastening mechanism
154:Socket of a bayonet
16:Fastening mechanism
389:
381:
373:
362:
351:
330:, hence the name.
156:
148:
137:
129:
1159:
1158:
1123:Bayonet cap (BC)
1109:Bayonet cap (BC)
1101:21 mm 4 pin
891:
890:
399:Lightbulb sockets
176:bayonet connector
170:using a matching
121:
120:
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1308:
1299:. Archived from
1293:
1287:
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1284:
1282:
1261:
1255:
1254:
1252:
1244:
1203:Bi-pin lamp base
943:Dimension, etc.
931:
930:
922:
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916:
910:
899:
524:
523:
481:and other small
349:twist-lock mount
280:electrical cable
116:
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96:
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29:
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1504:
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1439:Further reading
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234:, parts of the
194:fitting in the
127:A bayonet mount
117:
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60:"Bayonet mount"
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1453:External links
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1358:. May 24, 2017
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920:DIN EN 60061-1
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485:, and in many
440:(although not
410:United Kingdom
408:including the
406:British Empire
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200:British Empire
196:United Kingdom
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2:
1501:
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1477:
1475:
1474:Types of lamp
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1249:
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1239:
1229:
1226:
1224:
1223:BNC connector
1221:
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1209:
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836:
833:
831:BA21-3(120°)
830:
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823:
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811:
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450:United States
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160:bayonet mount
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83:
79:
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62: –
61:
57:
56:Find sources:
50:
46:
40:
39:
34:This article
32:
28:
23:
22:
19:
1426:February 15,
1424:. Retrieved
1420:the original
1409:
1397:
1396:
1389:. Retrieved
1385:www.beuth.de
1384:
1360:. Retrieved
1351:
1327:
1317:
1305:. Retrieved
1301:the original
1291:
1281:September 7,
1279:. Retrieved
1265:
1259:
1242:
1228:Edison screw
1213:Arri bayonet
1188:
1173:
1164:
1160:
934:Designation
927:
914:
906:
897:
698:7004-11A-10
637:7004-150B-1
625:7004-150A-1
527:Designation
510:
506:
503:
495:
491:Edison screw
446:Edison screw
403:
317:
308:
276:
268:
265:
261:
257:
189:
175:
159:
157:
107:
98:
88:
81:
74:
67:
55:
43:Please help
38:verification
35:
18:
1218:Joseph Swan
1191:CD spindles
1155:22 mm
1115:22 mm
1089:21 mm
1076:20 mm
1063:20 mm
1050:15 mm
1010:15 mm
905:list under
871:7004-10A-2
809:7004-173-1
797:7004-11D-1
773:7004-11C-3
760:7004-11B-7
735:7004-11E-1
661:7004-150-1
649:7004-149-1
563:7004-140-1
487:flashlights
434:Middle East
426:New Zealand
334:Light bulbs
236:Middle East
232:New Zealand
1468:Categories
1234:References
1184:lens mount
1170:Other uses
996:9 mm
956:5 mm
907:Amendments
883:7004-17-3
858:7004-10-7
834:7004-13-4
821:7004-12-7
747:7004-18-1
711:7004-19-2
685:7004-18-1
575:7004-14-9
550:7004-15-2
499:wedge base
483:indicators
473:models of
391:See also:
345:with GU10
202:including
192:light bulb
172:lens mount
101:April 2012
71:newspapers
1479:Fasteners
1391:April 23,
1362:April 23,
1307:April 12,
940:Contacts
615:49640-22
612:7004-9-1
602:49640-21
599:7004-8-1
519:DIN 49xxx
515:IEC 60061
430:Hong Kong
414:Australia
343:LED lamps
320:al-Jazari
224:Sri Lanka
208:Hong Kong
204:Australia
1399:Replaces
1275:Archived
1197:See also
903:Replaces
787:49720-4
763:49720-2
750:49720-3
725:49720-5
324:bayonets
269:Bayonet
220:Pakistan
1176:cameras
1134:B22d-3
1028:BAX15s
909:section
782:BAZ15d
757:BAY15d
744:BAX15d
720:BAU15s
634:BAUZ9s
422:Ireland
314:History
228:Ireland
145:bayonet
85:scholar
1180:lenses
1147:BX22d
1106:BA22d
1094:B21-4
1081:BA21d
1068:BA20d
1055:BA20s
1001:BA15d
974:BAX9s
880:BY22d
861:49740
848:49740
824:49730
770:BAZ15
732:BAW15
708:BAU15
701:49720
688:49721
675:49721
658:BAZ9s
646:BAW9s
622:BAU9s
609:BAY9s
596:BAX9s
589:49715
553:49710
462:Greece
458:France
454:Mexico
442:Canada
438:Africa
424:, and
347:bi-pin
328:rifles
302:, and
290:, and
254:Design
248:Greece
244:France
240:Africa
168:camera
87:
80:
73:
66:
58:
1348:(PDF)
1251:(PDF)
1208:Storz
1174:Many
1120:BC-3
987:BA9s
961:BA7s
948:BA5s
855:B22d
843:B22s
818:BA20
695:BA15
682:B15d
670:B15s
584:BA9s
418:India
288:video
284:audio
216:India
185:serif
174:) or
166:to a
92:JSTOR
78:books
1428:2009
1413:see
1393:2020
1364:2020
1309:2013
1283:2008
901:See
572:BA9
547:BA7
541:ANSI
460:and
452:and
436:and
292:data
246:and
238:and
230:and
212:Fiji
164:lens
64:news
1356:IEC
536:DIN
531:IEC
509:or
296:BNC
47:by
1470::
1395:.
1383:.
1372:^
1354:.
1350:.
1336:^
1326:.
1273:.
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1193:.
1152:2
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1126:2
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1086:2
1073:2
1060:1
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1033:1
1020:2
1007:2
993:1
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521:.
428:,
420:,
416:,
412:,
304:ST
298:,
286:,
250:.
226:,
222:,
218:,
214:,
210:,
206:,
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1430:.
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511:d
507:s
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300:C
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89:·
82:·
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41:.
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