Sensibly equivalent¶ to:
The HL2K is a battery triode with a bright anode box and a B4 base. The original HL2 from M-OV was released in 1931 with the HL2K following in 1934. The design function was as a detector of AF voltage amplifier. The ratings are identical between the HL2 and HL2K
The wide glass tube envelope is 27 mm in diameter and, excluding the B4 base pins, is 69 mm tall.
References: Private communication, 3002 & 4001. Type HL2K was first introduced in 1934. See also 1934 adverts.
Absolute Maximum Operating Conditions¶
Updated April 03, 2015.