+**5c4** is a type of [Vacuum Tube](/wiki/Vacuum_Tube) once prevalent in early electronic equipment. Primarily functioning as a half-wave [Rectifier](/wiki/Rectifier), it was crucial for converting alternating current into usable direct current within a circuit.
+## See also
+- [Electronics](/wiki/Electronics)
+- [Tube Amp](/wiki/Tube_Amp)
+- [Power Supply](/wiki/Power_Supply)