The 6BW4 is a full wave rectifier. The predecessor was the 7Z4 and a 12 volt version was made the 12BW4 with a 12.6 0.45 A heater designed for in-car applications.
The data-sheet gives operating details for both capacitor input filter and choke input filter configurations.
The Sylvania name and the twin rectifier sections.
One anode face view.
The thin glass tube envelope is 20 mm in diameter, and excluding the B9A base pins is 59 mm tall.
References: Data-sheet & 3002. Type 6BW4 was first introduced in 1955. See also1955 adverts.
