Sensibly equivalent¶ to:
The 7C6 is a double diode triode, and no specific design use is quoted. Normally such a valve would be used as signal and AGC detector plus first audio amplifier stage in broadcast receivers. This valve is unusual in that the anode impedance is high, maybe this valve was to be used for video demodulation and amplification.
The design dates to the late 1930's in America and the Uk versions are post-war.
The electrodes are obscured by the gettering but an example at radiomuseum.org shows the layout as a central cylindrical triode and inverted U shaped anodes for the diodes with the working area of the diodes at the top of the envelope. The 6AT6 on the B7G base uses the same layout.
The wide glass tube envelope is 28 mm in diameter and, excluding the B8B base pins, is 54 mm tall.
References: Datasheet, 1040 & 3002. Type 7C6 was first introduced in 1938.
Absolute Maximum Operating Conditions¶
Updated August 24, 2015.