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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
|  |  |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| L12 | Midget Triode |  |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| L225 | AF Triode | 1926 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| L240 | Output Triode | 1925 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| L30 | Triode | 1934 |   | 
 | CV3534 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| L4 | Triode |   |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| L525 | Output Triode | 1925 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| L550 | Output Triode | 1925 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| L71 | Triode |   | IO | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LA16-2 | Forward Wave Amplifier | 1959 |   | 
 | 7639 | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LA16-2C | Forward Wave Amplifier | 1962 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LA4-2 | Forward Wave Amplifier | 1959 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LA4-250 | Forward Wave Amplifier | 1959 |   | 
 | 7637 | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LA9-3 | Forward Wave Amplifier | 1960 |   | 
 | 7638 | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LB4-2 | Forward Wave Amplifier | 1959 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LB4-8 | Forward Wave Amplifier | 1959 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LB6-12 | Forward Wave Amplifier | 1960 |   | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LCF86 | Triode Pentode |   |   | 
 | 5HG8 | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LD1 | UHF Triode | 1941 |  | 
 | 12C3C | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LD15 | Triode |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LDR03 | Light Dependent Resistor |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| L.F. | Bi-Grid | 1927 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LF210 | AF Triode | 1927 | B4 | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LF2(White Line) | AF Triode | 1927 |   | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LF4(White Line) | AF Triode | 1927 |   | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LF407 | AF Triode | 1928 | B4 | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LF607 | AF Triode | 1928 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LF6(White Line) | AF Triode | 1927 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LL525 | Output Triode | 1927 |   | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LN119 | Triode Pentode |   |   | 
 | 10PL12 50BM8 UCL82 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LN319 | Triode Pentode |   |   | 
 | 13GC8 30PL1 PCL801 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LS1 | Triode | 1923 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LS1 | Pentode | 1940 |   | 
 | LN30000 | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LS2 | Triode | 1923 |   | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LS2 | Double Triode | 1940 |   | 
 | LN30001 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LS680 | Bi-Grid | 1927 |   | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LS7 | Repeater Triode | 1929 |   | 
 | CV1660 POVT82 | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LS7B | Repeater Triode |   | B4 | 
 |   | 
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| 
| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LSD2 | Flash Tube |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LSD3 | Flash Tube |   |  | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LSD7 | Flash Tube |   |  | 
 |   | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LSD8 | Flash Tube | 1949 | UX4 | 
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| Type | Structure | Date | Base | PDF | Sensibly equivalent¶ to: |  
| LZ339 | Triode Pentode | 1959 |   | 
 | 30C15 9EN7 LZ319 PCF800 | 
 |