H01T1/00	7	Details of spark gaps	H01T1/00	H01T1/00		487
H01T1/02	8	Means for extinguishing arc	H01T1/02	H01T1/02		255
H01T1/04	9	using magnetic blow-out	H01T1/04	H01T1/04		294
H01T1/06	10	with permanent magnet	H01T1/06	H01T1/06		56
H01T1/08	9	using flow of arc-extinguishing fluid	H01T1/08	H01T1/08		194
H01T1/10	10	with extinguishing fluid evolved from solid material by heat of arc	H01T1/10	H01T1/10		253
H01T1/12	8	Means structurally associated with spark gap for recording operation thereof	H01T1/12	H01T1/12		225
H01T1/14	8	Means structurally associated with spark gap for protecting it against overload or for disconnecting it in case of failure (H01T1/15, H01T1/16, H01T1/18 take precedence; emergency protective circuit arrangements for spark gap arrestors H02H7/24)	H01T1/14	H01T1/14		1024
H01T1/15	8	for protection against excessive pressure	H01T1/15	H01T1/15		196
H01T1/16	8	Series resistor structurally associated with spark gap	H01T1/16	H01T1/16		279
H01T1/18	8	Electrolytic device structurally associated with spark gap	H01T1/18	H01T1/18		93
H01T1/20	8	Means for starting arc or facilitating ignition of spark gap	H01T1/20	H01T1/20		249
H01T1/22	9	by the shape or the composition of the electrodes	H01T1/22	H01T1/22		366
H01T1/24	8	Selection of materials for electrodes (H01T1/22 takes precedence)	H01T1/24	H01T1/24		134
H01T2/00	7	Spark gaps comprising auxiliary triggering means (triggering circuits H01T15/00)	H01T2/00	H01T2/00		135
H01T2/02	8	comprising a trigger electrode or an auxiliary spark gap	H01T2/02	H01T2/02		587
H01T4/00	7	Overvoltage arresters using spark gaps (H01T2/00 takes precedence; overvoltage protection circuits using spark gaps H02H9/06)	H01T4/00	H01T4/00		96
H01T4/02	8	Details	H01T4/02	H01T4/02		463
H01T4/04	8	Housings (H01T4/06 takes precedence)	H01T4/04	H01T4/04		278
H01T4/06	8	Mounting arrangements for a plurality of overvoltage arresters	H01T4/06	H01T4/06		675
H01T4/08	8	structurally associated with protected apparatus (with switches H01H9/14; with fuses H01H85/44)	H01T4/08	H01T4/08		827
H01T4/10	8	having a single gap or a plurality of gaps in parallel	H01T4/10	H01T4/10		601
H01T4/12	9	hermetically sealed	H01T4/12	H01T4/12		810
H01T4/14	9	Arcing horns (associated with insulators H01B17/46)	H01T4/14	H01T4/14		222
H01T4/16	8	having a plurality of gaps arranged in series	H01T4/16	H01T4/16		530
H01T4/18	9	Arrangements for reducing height of stacked spark gaps	H01T4/18	H01T4/18		135
H01T4/20	9	Arrangements for improving potential distribution	H01T4/20	H01T4/20		326
H01T7/00	7	Rotary spark gaps, i.e. devices having one or more rotating electrodes	H01T7/00	H01T7/00		75
H01T9/00	7	Spark gaps specially adapted for generating oscillations	H01T9/00	H01T9/00		141
H01T11/00	7	Spark gaps specially adapted as rectifiers	H01T11/00	H01T11/00		175
H01T13/00	7	Sparking plugs	H01T13/00	H01T13/00		111
H01T13/02	8	Details	H01T13/02	H01T13/02		271
H01T13/04	9	Means providing electrical connection to sparking plugs	H01T13/04	H01T13/04		981
H01T13/05	10	combined with interference suppressing or shielding means	H01T13/05	H01T13/05		589
H01T13/06	9	Covers forming a part of the plug and protecting it against adverse environment	H01T13/06	H01T13/06		435
H01T13/08	9	Mounting, fixing or sealing of sparking plugs, e.g. in combustion chamber	H01T13/08	H01T13/08		801
H01T13/10	10	by bayonet-type connection	H01T13/10	H01T13/10		6
H01T13/12	9	Means on sparking plugs for facilitating engagement by tool or by hand	H01T13/12	H01T13/12		114
H01T13/14	9	Means for self-cleaning	H01T13/14	H01T13/14		642
H01T13/16	9	Means for dissipating heat	H01T13/16	H01T13/16		727
H01T13/18	9	Means for heating, e.g. for drying	H01T13/18	H01T13/18		110
H01T13/20	8	characterised by features of the electrodes or insulation	H01T13/20	H01T13/20		1247
H01T13/22	9	having two or more electrodes embedded in insulation (sparking plugs having two or more spark gaps H01T13/46)	H01T13/22	H01T13/22		170
H01T13/24	9	having movable electrodes (H01T13/28 takes precedence)	H01T13/24	H01T13/24		547
H01T13/26	10	for adjusting spark gap otherwise than by bending of electrode	H01T13/26	H01T13/26		62
H01T13/28	9	having spherically shaped electrodes, e.g. ball-shaped	H01T13/28	H01T13/28		42
H01T13/30	10	mounted so as to permit free movement	H01T13/30	H01T13/30		5
H01T13/32	9	characterised by features of the earthed electrode	H01T13/32	H01T13/32		1287
H01T13/34	9	characterised by the mounting of electrodes in insulation, e.g. by embedding	H01T13/34	H01T13/34		649
H01T13/36	9	characterised by the joint between insulation and body, e.g. using cement	H01T13/36	H01T13/36		683
H01T13/38	9	Selection of materials for insulation	H01T13/38	H01T13/38		617
H01T13/39	9	Selection of materials for electrodes	H01T13/39	H01T13/39		1274
H01T13/40	8	structurally combined with other devices (combined or associated with fuel injectors F02M57/06; structurally combined with other parts of internal-combustion engines F02P13/00)	H01T13/40	H01T13/40		442
H01T13/41	9	with interference suppressing or shielding means	H01T13/41	H01T13/41		278
H01T13/42	9	with magnetic spark generators	H01T13/42	H01T13/42		143
H01T13/44	9	with transformers, e.g. for high-frequency ignition	H01T13/44	H01T13/44		291
H01T13/46	8	having two or more spark gaps	H01T13/46	H01T13/46		64
H01T13/462	9	{in series connection}	H01T13/46	H01T13/46		302
H01T13/465	10	{one spark gap being incorporated in the sparking plug}	H01T13/46	H01T13/46		290
H01T13/467	9	{in parallel connection}	H01T13/46	H01T13/46		1347
H01T13/48	8	having means for rendering sparks visible	H01T13/48	H01T13/48		156
H01T13/50	8	having means for ionisation of gap (H01T13/52 takes precedence)	H01T13/50	H01T13/50		377
H01T13/52	8	characterised by a discharge along a surface	H01T13/52	H01T13/52		533
H01T13/54	8	having electrodes arranged in a partly-enclosed ignition chamber	H01T13/54	H01T13/54		819
H01T13/56	8	characterised by having component parts which are easily assembled or disassembled	H01T13/56	H01T13/56		132
H01T13/58	8	Testing (testing characteristics of the spark in internal-combustion engine ignition F02P17/12)	H01T13/58	H01T13/58		314
H01T13/60	9	of electrical properties	H01T13/60	H01T13/60		136
H01T14/00	7	Spark gaps not provided for in groups H01T2/00&#160;-&#160;H01T13/00(devices providing for corona discharge H01T19/00)	H01T14/00	H01T14/00		89
H01T15/00	7	Circuits specially adapted for spark gaps, e.g. ignition circuits (ignition circuits for internal-combustion engines F02P; electric spark ignition for combustion apparatus F23Q; protection circuits using spark gaps H02H9/06)	H01T15/00	H01T15/00		255
H01T19/00	7	Devices providing for corona discharge (for charging electrographic elements G03G15/02)	H01T19/00	H01T19/00		1153
H01T19/02	8	Corona rings	H01T19/02	H01T19/02		101
H01T19/04	8	having pointed electrodes	H01T19/04	H01T19/04		1841
H01T21/00	7	Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs	H01T21/00	H01T21/00		210
H01T21/02	8	of sparking plugs	H01T21/02	H01T21/02		1618
H01T21/04	9	Cleaning (means for self-cleaning H01T13/14; abrasive blasting devices for cleaning sparking-plugs B24C3/34)	H01T21/04	H01T21/04		204
H01T21/06	8	Adjustment of spark gaps (sparking-plugs having movable electrodes for adjusting the gap H01T13/26)	H01T21/06	H01T21/06		101
H01T23/00	7	Apparatus for generating ions to be introduced into non-enclosed gases, e.g. into the atmosphere	H01T23/00	H01T23/00		2652
