Current consumption of Voltmeter for OPHIR

[Tw15t3r]

I'm planning out an OPHIR-based LPM driver circuit that powers both the OPHIR itself and a voltmeter (which I'm getting off ebay) from 4x 1.5V alkaline batteries, and I need to make some provision for powering the voltmeter. I noticed that most people who are using the OPHIR-based LPMs are using an LED digital display voltmeter. So, how much current does the meter itself consume?

By my calculations, I was looking at something around ~240mA to light up "2.888" on such a display, assuming each digital segment (including the decimal point) uses 8mA of current. It's a bit on the high side though, so if anybody can help me verify, I'd have a slightly easier time with the OPHIR driving circuit.

(Just note that I'm not referring to LCD ones, which you can't see in the dark)

 

[lasersbee]

I'm planning out an OPHIR-based LPM driver circuit that powers both the OPHIR itself and a voltmeter (which I'm getting off ebay) from 4x 1.5V alkaline batteries, and I need to make some provision for powering the voltmeter. I noticed that most people who are using the OPHIR-based LPMs are using an LED digital display voltmeter. So, how much current does the meter itself consume?

By my calculations, I was looking at something around ~240mA to light up "2.888" on such a display, assuming each digital segment (including the decimal point) uses 8mA of current. It's a bit on the high side though, so if anybody can help me verify, I'd have a slightly easier time with the OPHIR driving circuit.

(Just note that I'm not referring to LCD ones, which you can't see in the dark)

Not all LED displays are identical in supply current draw.
I have had some LED DPMs here that were drawing as
low as ~30mA and others that drew up to ~180mA.
You can read the data sheet of the particular LED DPM you
choose.
As to not being able to see LCD displays in the dark...
the key word would be backlight...


Jerry

 

[Tw15t3r]

I see. The voltmeter I'm looking to get off ebay didn't specify how much the current draw is, so I thought I'd ask here. 30-180? Wow that's quite a range. Does it happen to have any relation to colours? Like maybe red draws less or something?