GEC was the trade name of M-OV valves destined for the professional equipment market. The Type is given as EF91/Z77 as the EF91 was the generic name for this valve type.It is a high gain, high impedance, high slope, screened pentode, primarily intended for use as RF amplifiers or mixer valves in VHF television receivers.![](../pics/aai0307a.jpg)
The GEC label.The thin glass tube envelope is 17 mm in diameter and, excluding the B7G base pins, is 46 mm tall.References: Data-sheet & 1040 Type EF91 was first introduced in 1947. See also 1947 adverts. |