Hi. Seems a nicely made calculator, I can interact to a certain point, but need help to use it from 0V for bottom led lit to 1.0V for the tenth led lit. The dot mode and other selections work fine.
Hi. Seems a nicely made calculator, I can interact to a certain point, but need help to use it from 0V for bottom led lit to 1.0V for the tenth led lit. The dot mode and other selections work fine.
hi,
If you look at the attached circuit diagram for the LM3914 you will see it uses an internal 1.25V reference voltage.
If you want a 1 Vin to set LED10 ON, use a +0.9V Vref for Pin #6 [RHi], connect a 1k2 resistor across pins #7 and #8, with Pin #8 also to 0V [ this sets the LED current to approx 10mA].
Lighting the LED on Pin #1, for a 0Vin will be a problem, as RLo, Pin #4 has a internal 1K.
One option would be to apply a +0.25V Offset onto the Vin voltage, this would make Vin appear as +0.25V thru 1.25V.
In that way you could use Pin #6 as normal ie: use the internal +1.25V.
The question was more about the use of the tool; which of its window fields are use selectable and which are calculated results. Found some fields reverting to defaults, and unclear use instructions.
The question was more about the use of the tool; which of its window fields are use selectable and which are calculated results. Found some fields reverting to defaults, and unclear use instructions.