6BR5

6BR5 is also designated EM80. Completed sales put the typical price at $18.00 per tube.

Description

The 6BR5 is an electronic tuning indicator, an all-glass miniature tube with nine contact pins on a wafer base, intended for use in AM and FM receivers or other electronic devices as an electro-optical zero or level indicator. The tuning condition is observed perpendicular to the tube axis on a funnel-shaped screen, where maximum tuning corresponds to the maximum luminous area (minimum shadow sector).

Construction

The tube comprises a triode control system and an indicator system, both sharing a common cathode. The indicator system has two deflectors that are interconnected and internally connected to the anode of the control triode. The tube has indirect heating with an oxide cathode.

Ratings

The heater is rated at 6.3 V and draws 0.3 A; the tube can be used with parallel or series DC or AC heater supply. The input capacitance is 2.9 pF and the transfer capacitance is 1.1 pF. Maximum ratings include a cathode current of 4 mA, a grid circuit resistance of 3 MΩ, a voltage between cathode and heater (DC or peak AC) of 100 V, an external resistance between cathode and heater of 20 kΩ, a cold anode voltage of 550 V, an operating anode voltage of 300 V, an anode dissipation of 0.2 W, a cold screen voltage of 550 V, an operating screen voltage of 300 V, and a minimum operating screen voltage of 160 V. The minimum anode load resistance is 200 kΩ. The maximum grid bias for the onset of grid current (Ig1 = +0.3 μA) is -1.3 V.

Characteristics

With an anode voltage of 100 V, screen voltage of 100 V, and grid bias of 2 V, the anode current is between 0.7 and 4.8 mA, the transconductance is greater than 0.7 mA/V, and the internal resistance is 19 kΩ. With a screen voltage of 250 V, an anode load resistor of 0.5 MΩ, and a grid resistor of 3 MΩ, the screen current is less than 3.8 mA.

Equivalence is asserted only where the archive's own literature states it directly, in at least 40 separate documents. Tubes that merely substitute in some circuits are not listed here.

Per-tube prices from completed sales, 2026-02-16 to 2026-09-17. Matched pairs and quads are divided out. See the price index for how these move over time.

Original manufacturer datasheets for 6BR5, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• 6BR5
• MINISTERSTVO PŘESNÉHO STROJÍRENSTVÍ (filed under EM80)

1 further designation appears alongside 6BR5 in the literature but below the evidence threshold used here, so it is not listed as equivalent.