74141 decimal place

[John Snow]

I'm trying to use 74141 drivers (intentionally), they have enough outputs to drive 0-9 per tube; but not including a display point.

I'm hoping to use a seperate driver to drive the display points (with an approproate resistor to reduce the current from numerical display levels)

Will this mean I can only have one decimal point active at a time?

I don't have the parts to breadboard yet, so stuck to theoretical.

[Kevin A.]

You could add an MPSA42 for each extra decimal point. Or use a chip with more outputs like any of the Microchip HV series (5522,5530,5523, etc). 

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[Paul Andrews]

On most tubes, you only need an additional resistor on the decimal point if it can be turned on with no digit being turned on at the same time. If it is only ever on when a digit is on, you will not need an additional resistor. I have no idea why.

Of course, this also means that if you want to display the decimal point both with and without a digit being turned on, you will need two paths to ground for it.

But yes, if you use one 74141 for all the decimal points, you would only be able to display one at a time.

[John Snow]

Great, that's what I thought it meant.

Now I'm tempted to skip having a decimal point, and avoid the extra hassle of an additional 74141 & 74HC595 to drive it.

[David Forbes]

The 74141 was created back in the Switch Age, when a rotary switch was used to select which digit had the point.

What do you want to use the decimal point for?

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[John Snow]

Right now, nothing, but I like wire up or breakout connections for later use.

It's less forward-planning and more not getting in my own way later.