The earlier naval valves, which usually also had an anchor symbol printed on the glass bulb, omitted the 'N' from the type.
The tables below provide brief details of UK Government valves issued before the introduction of the CV Register in 1941. The nearest commercial equivalent is provided for most of them, although, the commercial types were often modified, including change of base. Most of the valves were later given CV numbers and these have also been included in the tables.
UK Government Valves |
Type | Commercial Equivalents | Filament | Description & Comments | Base |
| | Volts | Amps | | Type | Ref |
Navy |
Note: for Loctal B8G read B8B, USS & USM = UX, Y8A = Footless |
ND3 | | 1.0* | 0-13 | Diode | B4 | - |
| GDT4C (Cossor) | 4.0 | 1.75 | Argon-filled thyratron | B5+tc | 9 |
| | 4.0 | 1.3 | Thyratron | B5 | 1 |
NGT3 = CV1142 | MR75 (Edi) | 2.0* | 10.0 | Thyratron | 4-pin | - |
NGT4 = CV1143 | GT1A (MOV) | 4.0 | 1.30 | Argon-filled thyratron | B5 | 1 |
NGT5 = CV1144 | BT19 (BTH) | 2.5* | 5.0 | Mercury vapour thyratron | B4+tc | 35 |
NGT6 = CV1145 | BT9 (BTH) | 5.0 | 20.0 | Mercury vapour thyratron. Double-ended | - | - |
NGT6A = CV1146 | | 5.0* | 20.0 | Thyratron | None | - |
NGT7 = CV1147 | BT5 (BTH) | 5.0 | 5.0 | Mercury vapour thyratron | USM4b+tc | 25 |
NGT8 = CV1148 | E1289 (MOV) | 2.5* | 43.0 | Mercury vapour thyratron | Special | - |
NGT9 = CV1149 | | 5.0 | 35.0 | Thyratron | None | - |
| | 4.0* | 0.10 | Low-μ triode | Clips | - |
|
NR15 = CV1151 | PM3 (Mul) | 3.6* | 0.12 | Triode | B4 | 1 |
| L410 (MOV), PM4DX (Mul) | 3.8* | 0.10 | Triode | B4 | 1 |
NR16 = CV1153 | PM254 (Mul) | 3.6* | 0.30 | Output triode | B4 | 1 |
NR16A = CV1154 | P425 (MOV), P425 (Edi), PM254 (Mul) | 3.6* | 0.25 | Output triode | B4 | 1 |
NR17 = CV1155 | | 4.0* | 0.10 | Low-μ triode | B4 | 1 |
NR18 = CV1156 | DEQ (MOV) | 3.0* | 0.22 | Triode | Clips | - |
NR19 = CV1157 | Obsolete type. No data available | | | Tetrode | - | - |
NR22 = CV1158 | PM14 (Mul) | 3.6* | 0.10 | RF tetrode | B4+tt | 2 |
NR23 = CV1159 | S410 (MOV), PM14 (Mul) | 3.6* | 0.10 | RF tetrode | B4+tt | 2 |
NR26 = CV1038 | MHL4 (MOV), 164V (Mul) | 4.0 | 1.00 | AF triode | B5 | 1 |
NR27 = CV1160 | ML4 (MOV), 104V (Mul) | 4.0 | 1.00 | Output triode | B5 | 1 |
| ML4 (MOV), 104V (Mul) | 4.0 | 1.00 | NR27 (Special tests) | B5 | 1 |
|
NR28 = CV1019 | P215 (MOV), PM2 (Mul) | 2.0* | 0.15 | Output triode | B4 | 1 |
NR31 = CV399 | AC/HL (Maz), MH4 (MOV), 354V (Mul) | 4.0 | 1.00 | AF triode | B5 | 1 |
NR35 = CV1163 | PD220A (Maz) | 2.0* | 0.20 | Class B double triode | B7 | 10 |
NR37 = CV1164 | AC/SG (Maz), MS4 (MOV) | 4.0 | 1.00 | RF tetrode | B5+tt | 2 |
NR38 = CV1165 | VMS4 (MOV), VM4V (Mul) | 4.0 | 1.00 | VM RF tetrode | B5+tt | 2 |
NR39 = CV1118 | PT2 & KT2 (MOV), Pen220 (Maz) | 2.0* | 0.20 | Output pentode or beam tetrode | B5 | 6 |
NR40 = (CV1237) | PM24D (Mul) | 4.0* | 2.00 | Output pentode | B5 | 6 |
NR41 = CV1083 | 210VPT (Cos), VP21 (MOV), VP210 (Maz) | 2.0* | 0.10 | VM RF pentode | B7+tc | 4 |
NR42 = CV1166 | 220PA (Cos), LP2 (MOV), PM2A (Mul) | 2.0* | 0.20 | Output triode | B4 | 1 |
NR43 = CV1167 | PM24A (Mul) | 4.0* | 0.25 | Output pentode | B5 | 6 |
NR44 = CV1168 | 4XP (Cos), PX4 (MOV), AC044 (Mul), PP3/250 (Maz) | 4.0* | 1.00 | Output triode | B4 | 1 |
NR45 = CV1169 | | 4.0 | 1.00 | VM RF pentode | B7+tc | 5 |
|
NR46 = CV1170 | D41(MOV) | 4.0* | 0.30 | Double diode | B5 | 3 |
| PP5/400 (Maz), PX25 (MOV), DO24 (Mul) | 4.0* | 2.00 | Output triode | B4 | 1 |
| EBC33 (Mul) | 6.3 | 0.20 | Double diode triode | IO+tc | 29 |
| EF36 (Mul) | 6.3 | 0.20 | RF pentode | IO+tc | 8 |
NR50 = CV1171 | A40 (Maz), HA1 (MOV), AT4 (Mul) | 4.0 | 0.25 | Acorn triode | 5AA | 1 |
NR51 = CV1172 | VMP4G (MOV), VPVA (Mul) | 4.0 | 1.20 | VM RF pentode | B7+tc | 5 |
NR52 = CV1173 | AC/HL (Maz), MH4 (MOV), 354V (Mul) | 4.0 | 0.65 | Medium-μ triode | B5 | 1 |
NR53 = CV1174 | AC/Pen (Maz), KT42 (MOV), Pen4VA (Mul) | 4.0 | 1.00 | Output pentode | B7 | 24 |
NR54 = CV1175 | ZA1(MOV), AP4 (Mul) | 4.0 | 0.25 | Acorn pentode | 7AA | 1 |
NR54A = CV1176 | ZA1 (MOV), AP4 (Mul) | 4.0 | 0.25 | As NR54 (less stringent) | 7AA | 1 |
NR55 = CV1109 | HL13C (Mul), 4D1 (Bri) | 13.0 | 0.20 | Medium-μ triode | B7 | 23 |
NR56 = CV1178 | V503 (Maz), DA30 (MOV), DO30 (Mul) | 4.0* | 2.00 | Output triode | B4 | 1 |
|
| AC/P (Maz), ML4 (MOV), TT4 (Mul) | 4.0 | 1.00 | Low-μ triode | B5 | 1 |
NR58 = CV1180 | V312 (Maz) | 4.0 | 0.65 | Medium-μ triode | B5+tc | 13 |
NR59 = CV1181 | AC2/Pen (Maz), KT41 (MOV), PenA4 (Mul) | 4.0 | 2.00 | Output pentode or tetrode | B7 | 24 |
NR60 = CV1182 | H42 (MOV) | 4.0 | 0.60 | High-μ triode | B7+tc | 23 |
NR61 = CV1183 | W42 (MOV) | 4.0 | 0.60 | VM RF pentode | B7+tc | 6 |
NR62 = CV1184 | A373 (MOV) | 1.8* | 1.60 | Voltmeter diode (Small Edison Screw cap) | SES+tt | - |
| KTW62 (MOV) | 6.3 | 0.30 | VM RF tetrode | IO+tc | 8 |
NR65 = CV1282 | AC/S2Pen (Maz), MSP4 (MOV) | 4.0 | 1.00 | RF pentode | B7+tc | 5 |
NR66 = CV1187 | D41 (MOV) | 4.0 | 0.30 | Double diode | B5 | 3 |
NR67 = CV1280 | 6L7G, X64 (MOV) | 6.3 | 0.30 | VM heptode mixer | IO+tc | 2 |
| 6Q7G, DH63 (MOV) | 6.3 | 0.30 | Double diode triode | IO+tc | 29 |
NR69 = CV1103 | Y63 (MOV) | 6.3 | 0.30 | Tuning indicator | IO | 46 |
|
NR70 = CV1124 | MS/Pen (Cos), SP4 (Mul) | 4.0 | 1.00 | RF pentode | B7+tc | 5 |
NR71 = CV1129 | MS/PenT (Cos) | 4.0 | 1.00 | As NR70 (special high voltage tests) | B7+tc | 5 |
NR72 = CV1188 | N43 (MOV) | 4.0 | 2.00 | Output pentode | B7+tc | 15 |
| 6N7G, ECC31 (Mul) | 6.3 | 1.00 | Double triode | IO | 22 |
NR74 = CV1189 | AC6/Pen (Maz) | 4.0 | 1.75 | Beam power amplifier | B7+tc | 35 |
NR75 = CV1190 | AC/P4 (Maz) | 4.0 | 1.10 | Matched pair of NR94 | B5+tc | 9 |
NR76 = CV1191 | KTZ41(MOV) | 4.0 | 1.50 | RF tetrode | B7+tc | 30 |
| 6L6G, EL35 (Mul) | 6.3 | 1.35 | Output pentode | IO | 36 |
NR78 = CV581 | 6C5G | 6.3 | 0.30 | Medium-μ triode | IO | 20 |
NR78A = (CV1932) | 6J5G | 6.3 | 0.30 | Detector or AF amplifier triode | IO | 20 |
NR79 = CV1192 | Z62 (MOV) | 6.3 | 0.45 | RF pentode | IO+tc | 8 |
NR80 | E1148 = CV6 | | | Superseded by VR135 | - | - |
|
NR81 = CV1941 | 6K7G | 6.3 | 0.30 | VM RF pentode | IO+tc | 8 |
| X65 (MOV) | 6.3 | 0.30 | Triode hexode FC | IO+tc | 3 |
| 6J7G, KTZ63 (MOV) | 6.3 | 0.30 | RF tetrode or pentode | IO+tc | 8 |
NR84 = CV1194 | 41STH (Cos), AC/TH1 (Maz), X41 (MOV), TH4 (Mul) | 4.0 | 1.20 | Triode hexode FC | B7+tc | 3 |
NR85 = CV1186 | 6F6G, KT63 (MOV) | 6.3 | 0.70 | Output pentode or beam tetrode | IO | 36 |
NR86 = CV1195 | KTW63 (MOV) | 6.3 | 0.30 | VM RF tetrode | IO+tc | 9 |
NR87 = CV1196 | AC5/PenDD (Maz) | 4.0 | 2.00 | Double diode output pentode | B7+tc | 9 |
NR88 = CV1197 | RL18 (Mul) | 6.3 | 0.25 | VHF triode | B3G | 2 |
| AC/P4 (Maz) | 4.0 | 1.10 | Triode | B5+tc | 9 |
NR95 = CV1287 | KT32 (MOV) | 26.0 | 0.30 | Output beam tetrode | IO | 36 |
| STV280/80 (MOV) | | | Voltage stabiliser. 73V, 193V, 205V & 282V | B5 | 15 |
| | | | Voltage stabiliser. 97.5V nominal | B4 | 12 |
|
NS3 = CV1200 | 202 (MOV) | | | Current stabiliser. 0.2A, 120-200V | B4 | 6 |
NS4 = CV1201 | 4317 | | | Current stabiliser, 20mA, 100-115V | B4 | 12 |
NS5 = CV1202 | 304 (MOV) | | | Current stabiliser. 0.3A, 95-165V | ES | - |
NT17 = CV1205 | E1007 (MOV) | 4.0* | 2.50 | Power triode | B4 | 1 |
NT18 = CV1206 | | 6.0* | 4.00 | Power triode (60W dissipation) | L4 | 1 |
| | 17.0* | 5.65 | TX triode (450W dissipation). Double-ended | None | - |
NT20 = CV1208 | P625 (MOV), PM256 (Mul) | 6.0* | 0.25 | Output triode | B4 | 1 |
NT22B = CV1209 | | 27.0* | 48.0 | Silica TX triode (15kW dissipation) | None | - |
NT22C = CV1210 | | 27.0* | 48.0 | Silica TX triode (15kW dissipation) | None | - |
NT23B = CV1211 | | 12.5* | 18.7 | Silica TX triode (2.5kW dissipation) | None | - |
NT23D = CV1212 | | 12.5* | 18.7 | Silica TX triode (2.5kW dissipation) | None | - |
NT24 = CV1213 | | 16.5 | 28.00 | Silica TX triode (4.0kW dissipation) | None | - |
|
NT26 | | 12.5 | 28.0 | Silica TX triode (4.0kW dissipation) | None | - |
NT27 | | 14.0 | 6.5 | Silica TX triode 1.5kW dissipation) | None | - |
NT30 = CV1214 | | 27.0* | 48.0 | Silica TX triode (15kW dissipation) | None | - |
NT31 = CV1215 | | 16.5* | 28.3 | Silica TX triode (4kW dissipation) | None | - |
NT32A | | 23.0* | 47.0 | Silica TX triode (4.5kW dissipation) | None | - |
| | 23.0* | 47.0 | Silica TX triode (4.5kW dissipation) | None | - |
NT33 = CV1217 | = CV1215 | | | | None | - |
NT35 = CV1218 | | 29.0* | 52.0 | Silica TX triode (15kW dissipation) | None | - |
NT36 = CV1219 | DA100 (MWT), MZ1-100 (Mul) | 6.0* | 2.70 | Power triode (100W dissipation), later reduced to 1A | L4 | 1 |
NT37 = CV1220 | 4033A (STC) | 6.0 | 1.50 | Power triode (25W dissipation) | B5 | 1 |
NT38 = CV1293 | | 10.0* | 2.0 | TX pentode (75W dissipation) | T4+tc | 2 |
NT38A = CV1221 | PZ1-75 (Mul), SW75/Pen (Mazda), PT6 (MWT) | 10.0* | 2.00 | TX pentode (75W Dissipation) | T4+tc | 2 |
|
NT39 = CV1222 | | 10.0* | 1.65 | TX triode (75W Dissipation) | T4+tc | 1 |
NT40 = CV1223 | DET5 (MWT) | 4.0* | 2.00 | Power triode (25W dissipation) | B4 | 1 |
NT41A = CV1224 | | 9.1* | 20.3 | Silica TX triode (1kW dissipation) | None | - |
NT43 = CV1225 | | 20.0* | 19.5 | Silica TX triode (3.5kW dissipation) | None | - |
NT45 = CV1295 | | 10.0* | 29.0 | Silica TX triode (1.5kW dissipation) | None | - |
NT45A = CV1226 | | 9.5* | 20.4 | Silica TX triode (1.25kW dissipation) | None | - |
NT46 | | 20.0* | 19.5 | Silica TX triode (3.5kW dissipation) | None | - |
NT46R = CV1227 | | 15.5* | 40.0 | Silica TX triode (3.5kW dissipation) | None | - |
NT48 = CV1228 | | 12.5* | 18.7 | Silica TX triode (12kW dissipation) | None | - |
NT52 = CV1229 | | 3.0* | 6.0 | Silica split-anode magnetron | None | - |
NT54 = CV1230 | | 28.0* | 20.0 | Silica TX triode (3.5kW dissipation) | None | - |
NT55 | | 8.5* | 20.3 | Silica TX triode (1.75kW dissipation) | None | - |
|
NT57 = CV1231 | | 15.2* | 48.0 | Silica TX triode (1kW dissipation) | None | - |
NT57A = CV1232 | | 15.8* | 48.0 | Silica TX triode (1.75kW dissipation) | None | |
NT57D = CV1233 | DET5 (MWT) | 4.0* | 2.00 | TX triode | B4 | 1 |
NT57T = CV1234 | | 9.0* | 35.0 | TX triode | None | - |
| DET12 (MWT), TY1-50 (Mul) | 7.5* | 3.15 | RF amplifier or oscillator triode (100MHz max, 50W dissipation) | B4+2tc | 16 |
NT58A = CV1235 | TY1-50 (Mul), DET12 (MWT) | 7.5* | 3.15 | RF amplifier or oscillator triode (100MHz max, 50W dissipation) | B4+2tc | 16 |
NT59A = CV1236 | | 8.5* | 20.3 | TX pentode (1.75kW dissipation) | None | - |
NT62 = CV1237 | PM24D (Mul) | 4.0* | 2.00 | Output pentode | B5 | 6 |
NT62A = CV1238 | As Above | 4.0* | 2.00 | Output pentode | B5 | 6 |
NT63A = CV1239 | | 13.0* | 40.9 | TX pentode (2.5kW dissipation) | None | - |
NT65 = CV1240 | PT15 (modified) (MWT) | 4.0* | 2.45 | TX pentode (modified - 4V heater and base change) | T4+tc | 2 |
NT65A = CV1240 | PT15 (MWT) | 4.0* | 2.45 | TX pentode (modified - 4V heater and base change) | T4+tc | 2 |
|
NT68 = CV1241 | | 4.0* | 1.00 | Power triode (20W dissipation) | B4 | 1 |
NT68A = CV1242 | As NT68 with special cut-off test | 4.0* | 1.00 | As above | B4 | 1 |
NT69 = CV1243 | = NT63A | | | | None | - |
NT74 = CV1370 | PV1/35 (Mul), SW35/Pen (Maz) | 12.0 | 0.90 | TX pentode | B7+tc | 39 |
NT77A = CV50 | | 10.7* | 69.0 | Silica TX tetrode (200W dissipation | None | - |
NT77B = CV50 | | 10.7* | 69.0 | Silica TX tetrode (200W dissipation | None | - |
NT78A = CV1245 | | 10.0* | 65.0 | TX triode (300W dissipation | None | - |
| P2 (MOV), PM202 (Mul) | 2.0* | 0.20 | Output triode | B4 | 1 |
NT83 = CV1247 | | 14.0* | 6.00 | TX triode (150W dissipation) | None | - |
NT84 = CV1248 | | 12.5* | 40.8 | TX triode (1.5kW dissipation) | None | - |
NT86 = CV1249 | | 10.5* | | TX triode | None | - |
NT87 = CV1250 | 4279-A (STC) | 10.0* | 21.0 | TX triode (1.2kW dissipation) | 2pin+tc side cap | - |
|
NT90 = CV1251 | | 33.0 | 20.0 | TX triode (6kW dissipation) | None | - |
NT92 = CV1252 | 4212E (STC) | 14.0* | 6.25 | TX triode (275W dissipation). | USL4b | - |
NT93 = CV1253 | E1161 (MOV) | 12.0* | 10.6 | TX triode | None | - |
| E1265 | 11.0 | 12.25 | TX triode (17.5kW dissipation) | None | - |
| E1232 (MWT) | 6.0 | 6.50 | Triode with forced air cooling (150W dissipation) Micropup construction | None | - |
NT100 = CV1257 | E1155 (MWT) | 8.0 | 6.0 | Air-cooled modulator tetrode (60W dissipation) | 2-pin+tt | - |
NU2 = CV1259 | = U2 | 17.0* | 6.6 | Half-wave rectifier | None | - |
NU3 = CV 1064 | U12/14 (MOV), DW4/500 (Mul), UU120/350 (Maz) | 4.0* | 2.5 | Full-wave rectifier. Double-ended | B4 | 5 |
NU4 = CV1260 | Replaces NU1 where approved | 14.0* | 6.0 | Half-wave rectifier. Double-ended | - | - |
NU5 = CV1261 | RX3-120 (Mul) | 13.5* | 9.7 | Half-wave rectifier. Double-ended | None | - |
NU7 = CV1262 | GU1 (MOV) | 4.0* | 3.0 | Half-wave mercury-vapour rectifier | B4 | 4 |
NU8 = CV1263 | RG1-125 (Mul) | 2.0* | 5.0 | Half-wave mercury-vapour rectifier | ESM+tt | - |
|
| Formally U18 (MOV), FW4-500 (Mul) | 4.0* | 3.20 | Full-wave rectifier | B4 | 5 |
NU13 = CV1265 | U15 (MOV), RZ1-250 (Mul) | 6.0* | 2.0 | Half-wave rectifier | L4 | C |
| U15 (MOV), RZ1-250 (Mul) | 6.0* | 2.0 | Half-wave rectifier | L4 | C |
NU15 = CV1267 | 1D5 (Brimar), U4020 (Maz) | 40.0 | 0.20 | Half-wave rectifier | B5 | 8 |
NU16 = CV1072 | GU50 (MOV) | 4.0* | 3.00 | Half-wave mercury-vapour rectifier | B4+tc | 6 |
NU17 = CV1039 | 44IU (Cos), UU5 (Maz), MU12/14 (MOV), IW4 (Mul) | 4.0 | 2.50 | Full-wave rectifier | B4 | 14 |
NU17S = CV1296 | MU14 (MOV) | 4.o | 2.50 | Full-wave rectifier | B4 | 5 |
NU18 = CV1113 | U17 (MOV) | 4.0* | 1.00 | EHT half-wave rectifier | B4+tc | 6 |
NU20 = CV1268 | U50 (MOV) | 5.0* | 2.00 | Full-wave rectifier | IO | 60 |
NU21 | | 17.0* | 16.8 | Silica half-wave rectifier | None | - |
NU22 | | 19.0* | 19.0 | Silica half-wave rectifier | None | - |
NU22B = CV1269 | MU2 | 19.0* | 19.0 | Silica half-wave rectifier | None | - |
|
NU22C = CV1270 | | 19.0* | 19.0 | Silica half-wave rectifier | None | - |
NU23 = CV1271 | | 27.5* | 47.0 | Silica half-wave rectifier | None | - |
NU24 = CV1272 | | 22.0* | 52.0 | Silica half-wave rectifier | None | - |
NU25 = CV1273 | | 19.0* | 19.5 | Silica half-wave rectifier | None | - |
NU26 = CV1274 | | 22.0* | 18.0 | Silica half-wave rectifier | None | - |
NU26C = CV1275 | | 22.0* | 18.0 | Silica half-wave rectifier | None | - |
NU28 = CV1276 | | 28.0* | 20.0 | Silica half-wave rectifier | None | - |
NU29 = CV1277 | | 29.0* | 52.0 | Silica half-wave rectifier | None | - |
NU30 = CV1278 | | 14.0* | 10.0 | Silica half-wave rectifier | None | - |
NU31 = CV1279 | MU2 (Maz) | 2.0* | 3.10 | Mercury-vapour half-wave rectifier | B4+tc | 6 |
| SU2150A (Cos) | 2.0 | 1.50 | EHT half-wave rectifier | B4+tc | 17 |
NU33A = CV1291 | HVR2A (Mul) | 2.0 | 1.50 | EHT half-wave rectifier | B4+tc | 17 |
|
NU34 = CV1134 | HVR2 (Mul) | 4.0 | 0.65 | EHT half-wave rectifier | B4+tc | 17 |