+The 12a7 is a [miniature](/wiki/Miniature) [electron tube](/wiki/Electron_tube), uniquely combining a triode and a power pentode within a single glass envelope. It often served in compact audio amplifiers and radio circuits, providing both signal amplification and output power from one component.
+## See also
+- [Vacuum Tube](/wiki/Vacuum_tube)
+- [Amplifier](/wiki/Amplifier)
+- [Triode](/wiki/Triode)
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