The 3DB3 is a compact high-voltage half-wave glass diode rectifier tube designed for high-voltage power supply and flyback rectifier stages in series-string radio receivers, equipment power supplies, and high-voltage display circuits. Featuring an 8-pin Octal base layout with a top cap anode connection, it provides high inverse voltage handling with a 3.15V heater rating designed for controlled warm-up series circuits. Available in new old stock (NOS) and tested used conditions.