Section H: Electricity

Division H1: electrical circuit elements; magnets

H1A Electric cables and conductors

Series C & D file lists are available using:

the current Key Edition back to the operative date of Edition L
Edition K back to the specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H1B Electric cells of the electrochemical type

Part A

Series C & D file lists are available using the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Edition of the Key for UK specifications from serial number 1,000,000 to the year 1911.

Part B

Series C & D file lists are available as follows:

for terms annotated by a marginal code back to the operative date of the Edition corresponding to that code
for all other terms back to at least specification 200,000

H1C Stimulated-emission devices

Series C & D file lists are available using:

for classifying terms - the current Key Edition back to at least specification 200,000
for indexing terms annotated by a marginal code - the current Key Edition back to the operative date of the edition corresponding to that code
for all other indexing terms - the current Key Edition back to at least specification 200,000.

H1D Electric discharge tubes &c

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.

H1E Piezo-electric elements

Series C & D file lists are available using:

for terms annotated by a marginal code "k" - the current Key Edition back to the operative date of Edition K
for all other terms - the current Key Edition back to at least specification 200,000.

H1F Electric incandescent lamps

Series C & D file lists are available using:

for classifying terms - the current Key Edition back to at least specification 200,000
for indexing terms - the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H1J Turret machines for lamps &c

Series C & D file lists are available using the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H1K Electric solid-state devices &c

Series C & D file lists are available using:

for terms annotated by a marginal code "j" or "m" - the current Key Edition back to the operative date of the Edition corresponding to the code
for other terms - the current Key Edition back to at least specification 200,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H1M Capacitors and electrets &c

Series C & D file lists are available using:

for terms annotated by a marginal code - the current Key Edition back to the operative date of the Edition corresponding to that code
for all other terms - the current Key Edition back to at least specification 200,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H1N Electric switches &c

Series C & D file lists are available using the current Key Edition back to specification 200,000.

H1P Electromagnets, permanent magnets &c

Series C & D file lists are available using:

for classifying terms - the current Key Edition back to at least specification 200,000.
for indexing terms - the current Key Edition back to the operative date of Edition J, then Edition I back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H1Q Aerials &c

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.

H1R Printed circuits; electrical component assemblies

Series C & D file lists are available using the current Key Edition:

for terms annotated by a marginal code "q" - back to the operative date of Edition Q
back to at least specification 200,000.

H1S Ohmic resistors &c

Series C & D file lists are available using:

for classifying terms - the current Key Edition back to at least specification 200,000
for indexing terms annotated by a marginal code - the current Key Edition, back to the operative date of the Edition corresponding to that code
for other indexing terms - the current Key Edition back to the operative date of Edition A.

H1T Electric transformers &c

Series C & D file lists are available using the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H1W Electromagnetic waveguides &c

Series C & D file lists are available using:

for classifying terms, the current key edition back to specification 200,000
for indexing terms:

1. for those annotated by a marginal code "b" back to operative date of Edition B

2. for all others, back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H1X Miscellaneous discharge apparatus

Series C & D file lists are available using the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

Division H2: electric power

H2A Dynamo-electric machines &c

Series C & D file lists are available using:

the current Key Edition back to the operative date of Edition R
Key Edition Q back to the operative date of Edition K
for terms AQL (when applied to rotary machines), AMF and ARF in Key Edition J - back to specification 2,000,000. These file lists may be supplemented by using terms from Part B of Edition B
for other terms - Edition J back to at least specification 200,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H2C Electric and optic cable installations &c

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.

H2E Electric couplings &c

Series C & D file lists are available using the current Key Edition:

for terms ECFS and ECFX back to the operative date of Edition W
for terms EABC, EABP, EABX back to the operative date of Edition N
for all other terms back to at least specification 200,000.

H2F Electric converting systems

Series C & D file lists are available using:

for classifying terms annotated by a marginal code "o" - the current Key Edition back to the operative date of the Edition O
for classifying terms annotated by a marginal code other than "o" - the current Key Edition back to at least specification 200,000
for other classifying terms - the current Key Edition back to specification 1,000,000
for indexing terms annotated by the marginal code "I" - the current Key Edition back to the operative date of Edition I, then Edition H back to specification 1,000,000
for other indexing terms - the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H2G Electric cut-outs

Series C & D file lists are available using the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H2H Electricity supply systems &c

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.

H2J Electric motor operating arrangements

Series C & D file lists are available as follows:

for classifying terms annotated by a marginal code (except "t") - using the current Key Edition back to the operative date of the Edition corresponding to the code
for terms annotated by a marginal "t" - using the current Key Edition back to specification 200,000
for other classifying terms - using the current Key Edition back to specification 1,000,000
for classifying terms in Edition I - using Edition I back to specification 200,000
for indexing terms in Edition I annotated by a marginal code - using Edition I back to the operative date of the Edition corresponding to that code
for other indexing terms in Edition I - using Edition I back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H2K Electric protective systems

Parts A and B

Series C & D file lists are available using:

for all terms in the current Edition - the current Key Edition back to at least specification 200,000
for indexing terms included in the 1500 Key Edition but not in the current Key Edition - from the operative date of Edition A or Edition B back to 1911.

Note: in the 1500 Key Edition all indexing terms were non-discretionary and consequently file lists of discretionary indexing terms of the current Edition which were also included in the 1500 Key Edition will contain documents published before the operative date of Edition A where the disclosure is not of particular interest or significance.

Division H3: electronic circuits; radio receivers

H3A Automatic control of frequency and phase

Series C & D file lists are available using:

for classifying terms - the current Key Edition back to at least specification 200,000
for indexing terms - the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H3B Static, magnetic and dielectric storage systems and devices

Parts A and B

Series C & D file lists are available using:

for classifying and indexing terms - the current Key Edition back to specification 700,000
for terms in the 1500 indexing schedule - the 1500 Key Edition for specifications between 1,500,000 and 700,000.

H3F Oscillator

Parts A and B

Series C & D file lists are available using:

the current Key Edition back to the operative date of Edition K
Edition J back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H3G Control of amplification

Series C & D file lists are available using:

for indexing terms G15 - the current Key Edition back to the operative date of Edition L
for all other terms - the current Key Edition back to at least specification 200,000.

H3H Electric analogue-digital conversion

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.

H3P Pulse, logic and switching circuits

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.

Note: prior to Edition K, heading H3P was restricted to subject matter relating to pulse, logic and switching circuits employing electric discharge tubes. Subject matter relating to pulse, logic and switching circuits involving semiconductor or unspecified active elements was classified in heading H3T.

Series C & D file lists are still available using Edition J of H3P, back to specification 1,000,000 and using Edition J of H3T, back to at least specification 200,000.

Series A file lists are available using the 960 H3P Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H3Q Radio receivers &c

Series C & D file lists are available using:

for terms annotated by a marginal code "l" - the current Key Edition back to the operative date of Edition L
for indexing terms Q100 and Q101 - the current Key Edition back to the operative date of Edition A
for all other terms - the current Key Edition back to at least specification 200,000.

H3R Modulating; demodulating; frequency changing

Series C & D file lists are available using the current Key Edition back to specification 2,000,000 and Edition I back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H3T Indexing Schedule for amplifiers, oscillators, pulse, logic and switching circuits

Series C & D file lists are available using:

for terms annotated by a marginal code - the current Key Edition back to the operative date of the Key Edition corresponding to that code
for other terms - the current Key Edition back to at least specification 200,000.

H3U Impedance networks &c

Part A

Series C & D file lists are available using the current Key Edition:

for classifying terms back to at least specification 200,000
for indexing terms back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

Part B

Series C & D file lists are available using:

for terms annotated by a marginal code "a" the current Key Edition back to the operative date of Edition A
for other terms - the current Key Edition back to specification 1,000,000
for terms present in the 1500 Key Edition but not in the current Key Edition - from the operative date of Edition A back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

Part C

Series C & D file lists are available using:

for classifying terms - the current Key Edition back to the operative date of Edition K
for indexing terms - the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H3W Linear amplifiers; limiters

Parts A and B

Series C & D file lists are available using the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H3X Miscellaneous circuits &c

Series C & D file lists are available using the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

Division H4: telecommunications

H4B Optical communication

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.

H4D Wave-energy position finding &c

Series C & D file lists are available using:

for classifying terms - the current Key Edition back to specification 1,000,000
for indexing terms indicated by a marginal code "r" - the current Key Edition back to the operative date of Edition R
for all other indexing terms - the current Key Edition back to specification 200,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

Note: file lists for classifying terms DRPX, DRSB and DSPM from Edition I include specifications classified under Edition H classifying terms DRPT, DRCB and DSPG respectively.

H4F Pictorial communication

Series C & D file lists are available using the current Edition of the Key:

for classifying terms annotated by marginal codes "t" or "v" back to specification 2,000,000
for all other classifying terms back to specification 1,000,000
for indexing terms back to the operative date of Edition R.

Series C & D file lists are available using Edition Q of the Key:

for indexing terms indicated by the marginal codes "l" or "o" back to the operative date of the Edition corresponding to the code
for indexing terms indicated by the marginal codes "a" and "i" back to specification 1,000,000
for other indexing terms back to at least specification 200,000.

Series C & D file lists are available using the 1500 Key Edition back to at least specification 200,000.

H4J Audio transducers, local circuits &c

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.

H4K Telecommunication switching &c

Series C & D file lists are available using:

for terms indicated by a marginal code "l", "n" or "w" - the current Key Edition back to the operative date of the Edition corresponding to the code
for other terms - the current Key Edition back to at least specification 200,000 (although the earliest specifications on file lists may have been published much later since the subject matter of some classification terms involves recent technological developments).

H4L Electromagnetic and inductive field communication

Series C & D file lists are available using the current Key Edition

for classification terms annotated by a marginal code later than "k" back to specification 1,000,000
for all other classification terms back to at least specification 200,000
for indexing terms, back to the operative date of the respective Key Edition.

H4M Electric multiplexing techniques; distributors

Series C & D file lists are available using

for terms indicated by a marginal code "p" - the current Key Edition back to the operative date of Edition P
for other terms - the current Key Edition back to at least specification 200,000.

H4P Electric digital data transfer; telegraphy

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.

H4R Line transmission systems; signal processing

Series C & D file lists are available using the current Key Edition back to at least specification 200,000, except for term R22P for which the file list extends back to the operative date of Edition C.

H4T Cathode-ray tube circuits &c; image signal synthesis &c

Series C & D file lists are available using the current Key Edition back to about the year 1925.

H4X Sound magnifiers &c

Series C & D file lists are available using the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

Division H5: miscellaneous electric techniques

H5H Electric heating; microwave heating &c

Parts A and B

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.

Part C

Series C & D file lists are available using:

for terms annotated by the marginal code "I" - the current Key Edition back to the operative date of Edition I, then Edition H back to specification 1,000,000
for other terms - the current Key Edition back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

Part D

Part D was deleted at Edition R; see heading notes for where this subject matter is now classified.

Series C & D file lists are available using the Edition Q back to specification 1,000,000.

Series A file lists are available using the 960 Key Edition for UK specifications from serial number 1,000,000 back to the year 1911.

H5R Radiology; radiography; irradiation

Series C & D file lists are available using the current Key Edition back to at least specification 200,000.