6.8V globe replacement

[BKnut]

I have several Bruel & Kjaer vintage test equipment. Some of the white scale meter dials have stopped illuminating. The B&K globes are rated as 6.8V 0.25A. Thought of buying some old VW beetle globes if they had the same size. But prefer to build some being quicker. Photos are a little fuzzy.

 

[PRR]

White LEDs (back-to-back for AC) and 220 Ohm series resistor would last forever.

 

[BKnut]

I have several Bruel & Kjaer vintage test equipment. Some of the white scale meter dials have stopped illuminating. The B&K globes are rated as 6.8V 0.25A. Thought of buying some old VW beetle globes if they had the same size. But prefer to build some being quicker. Photos are a little fuzzy.

added photos

 

[BKnut]

White LEDs (back-to-back for AC) and 220 Ohm series resistor would last forever.

Thats for 110VAC, 240VAC would be double or 440ohms? 1/4W rating sufficent?

 

[audiofeline]

If you find the LED is too much of a "point" source, a diffuser could help (eg. some thin opal perspex).

 

[DUG]

I have several Bruel & Kjaer vintage test equipment. Some of the white scale meter dials have stopped illuminating. The B&K globes are rated as 6.8V 0.25A. Thought of buying some old VW beetle globes if they had the same size. But prefer to build some being quicker. Photos are a little fuzzy.

White LEDs (back-to-back for AC) and 220 Ohm series resistor would last forever.

Thats for 110VAC, 240VAC would be double or 440ohms? 1/4W rating sufficent?

220R was for the 6.8V, not 110 or 220

 

[PRR]

Thats for 110VAC,...

No, it's not.

And double voltage is not double Watts.

Stick with incandescent lamps.

 

[MAAC0]

Try here:

There's were I've got my vintage VU lamps

Incandescent

 

[BKnut]

Thanks Maaco, for your link. A 6.8V globe is a rare oddity.

 

[BKnut]

220R was for the 6.8V, not 110 or 220

I normally pick 20mA operating current for LEDS and subtract the LED voltage from 6.8V to calculate the resistor value.

However, with no small led on hand, I used a mini incandescent lamp which could only fit inside a 3AG glass fuse. No limiting resistor needed.