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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S08 | Triode | 1928 |   | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S103/1K | Thermal Switch | 1958 | B7G | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S104/1K | Thermal Switch | 1958 | B7G | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S12 | Midget Pentode | 1938 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S207/3K | Thermal Delay Switch |   |  | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S215A | Pentode | 1931 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S215B | Pentode | 1931 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S201A | Triode | 1927 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S22AF | Pentode | 1931 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S24 | Pentode | 1933 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S27A | Triode |   |   | 
 | CV82 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S4143P | Camera Tube |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S4145B | Camera Tube |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S4161P | Camera Tube |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S4250 | Camera Tube |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S.609C-59M | Camera Tube |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S610 | Pentode | 1929 |   | 
 | CV3698 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S6F12 | Pentode SQ EF91 | 1958 |   | 
 | CV4014 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| S6F17F | Beam Tetrode | 1961 |   | 
 | CV4041 L.5A/210F L.5A/210G | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SC1/1400 | Corona Voltage Stabiliser | 1959 | B7G | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SC1/400 | Corona Voltage Stabiliser | 1956 | B7G | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SC1/600 | Corona Voltage Stabiliser | 1956 |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SC1/2000 | Corona Voltage Stabiliser |   |   | 
 | CV6067 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SC2/3000 | Corona Voltage Stabiliser |   |  | 
 | CV5844 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SC5/6800 | Corona Voltage Stabiliser | 1965 |   | 
 | CV8960 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SD | Diode |   |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SD3 | Triode | 1933 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SD4 | Diode Tetrode | 1933 | B7 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SD61 | Diode |   |   | 
 | 6D1 EA50 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SE | Photocell |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SE211C | VM RF Tetrode | 1936 | B4 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SF8 | Flash Tube |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SG | Pentode |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SG2 | RF Tetrode | 1932 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SG207 | RF Tetrode | 1928 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SG410 | Pentode | 1928 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SG610 | Pentode | 1928 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SH342 | Thermal Delay Switch | 1946 | B7G | 
 | CV342 DLS19VLS631 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SK60 | Photocell | 1937 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SN4 | Strobotron |   |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP-16 Red+A4237 | Triode | 1928 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP1320 | Pentode | 1934 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP141 | Pentode | 1939 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP18(Blue Spot) | RCC Triode | 1926 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP18(Green Spot) | RF Triode | 1926 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP18(Red Spot) | Output Triode | 1926 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP.2 | Output Triode | 1930 | B4 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP2220 | Pentode | 1936 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP4B | HF Pentode | 1935 | B7 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP55(Blue Spot) | RF/RCC Triode | 1926 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP55(Red Spot) | Output Triode | 1926 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP55B | Triode | 1928 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SP610/G | Triode | 1928 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SPTA | Pentode | 1936 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS | Triode |   | B4 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS11A | Triode | 1927 |   | 
 | PM256 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS2HF | Triode | 1926 |   | 
 | D.3HF | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS3HF | Triode | 1926 |   | 
 | DE3B | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS4075HF | Triode | 1928 |   | 
 | PM3 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS425SP | Triode |   |   | 
 | PM254 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS4DGAC |   |   |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS4HLAC | Triode | 1933 |   | 
 | 224V | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS4MMAC | Pentode | 1932 |   | 
 | MM4V | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS501 | Flash Tube |   |  | 
 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS625SP | Triode | 1928 |   | 
 | PM256 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS625SPA | Triode | 1930 |   | 
 | PM256A | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SS9 | Triode | 1926 |   | 
 | PM5 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SSHV4/1 | Triode | 1931 |   | 
 | AC064 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SSHV6/5 | Triode | 1930 |   | 
 | D025 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SSU465 | Rectifier FW |   |   | 
 | DW4 | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SSU765 |   |   |   | 
 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SSW120/500 | Rectifier FW |   |   | 
 | DW4 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SSW432 | Rectifier FW |   |   | 
 | DW1 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| ST4 | Rectifier FW |   |   | 
 | CV1846 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| ST61 | Triode | 1926 |   | 
 | PM5 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| STR4B32 | Rectifier HW (Silicon) |   |  | 
 | 4B32 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SU42 | Rectifier EHT |   | IO | 
 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| Screen Grid | RF Tetrode | 1927 |   | 
 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SW75Pen | Pentode |   |   | 
 | ARP75 CV1221 NT38A PT6 PZ1-75 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SY11 | Klystron | 1960 |   | 
 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SY30 | Klystron | 1957 |   | 
 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SZ22 | Klystron | 1961 |   | 
 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SZ50 | Klystron | 1963 |   | 
 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| SZ53 | Reflex Klystron | 1963 |   | 
 |   | 
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