[volt-nuts] Neon bulbs for HP 3420B or 419A chopper

[Charles Steinmetz]

george wrote:

> Farnell (UK) list NE-2U neon lamps.

Note that the NE-2U is a "high brightness" lamp with a 135vDC (max) 
strike voltage.  Standard brightness lamps strike at 90vDC (max).  The 
Farnell site available to me here in the US lists the CML (Chicago 
Miniature Lamp) A3C, which CML list with NE-2U as the "Old Reference 
Number."

Farnell do not seem to carry the CML standard brightness lamps with 
reduced dark effect.  According to the CML datasheet, there are four 
part numbers with that combination:  A1D, A1D-T, A2B, and A2B-T.  "T" 
indicates tinned leads.  The design current of the A1 parts is 300uA, 
and of the A2 parts it is 700uA.  Check the schematic and you should be 
able to calculate the neon operating current of the circuit, and choose 
A1 or A2 accordingly.

Dave, perhaps Farnell will special order one of these part numbers for 
you.  If Farnell can't get you the right part, I believe both Mouser and 
Digi-Key operate in the UK and both have A1D(-T) and A2B(-T) parts in 
stock (in the UK, I think).

Cheers,

Charles