Electronics > Projects, Designs, and Technical Stuff
LM3914 - What is used now, how flexible are they?
(1/2) > >>
741:
I'd like to make a centre-zero led dot readout, 0 to 0.6V. The LM3914 has been around a while - perhaps because of features like current output and both sides of comparator string being available. How do more recent chips compare?

If I do end up using an LM3914, then is there a "known good" cheap source?

(While it is probably possible to program a PIC to replicate the comparators using an A/D and perhaps brightness using PWM...I'd prefer not to get into that just now).

The basic resolution of an LM3914 can be enhanced with brightness control - In this PDF (https://www.americanradiohistory.com/Archive-Electronics/Electronics-Circuit-Designers-Casebook-5.pdf), look for the phrase "display expands".
schmitt trigger:
The LM3914 is one of those "classic" linear bipolar devices which will always will have a loyal following for years to come.

Unfortunately it has been mostly superseded in most high-volume projects by other display technologies.

And even if you still want to employ discrete LED bargraphs, it is usually best to use a microcontroller and either drive it directly from its output ports, or use an I2C driver which allows many more features, like dimming, flashing and individual segment control.
Some driver ICs have so many outputs that an actual RGB bargraph can be implemented.

Related to sourcing; you may of course, obtain them from Ebay. Caveat emptor.
The best is to obtain them from a reputable distributor, although they will cost more.
austfox:
For those in Australia, Rockby have National branded LM3914s in DIP packages on their specials pages this month at 3 for $5.
Zero999:
An array of LM339s, some resistors and a voltage reference will give you a basic bargraph display, but not dot mode, will require more parts.

Why not just use a microcontroller? It will work out much easier and cheaper. The LM3914 is dead because no one uses it in new commercial products any more. Updating ones skills to use modern components is vital for continuing to progress.
Yansi:
I'd like to correct a bit: The LM3914 (linear mode) is the only one of the series currently still being produced by Texas Instruments, if I am not mistaken. So probably, someone is using them somewhere.

LM3915 (the log one, for audio purposes) is no longer made. But most audio equipment used chained LM339 comparators with a precision opamp rectifier in front of them - no wonder, as the pricing of the LM3915 at utmost respect is (or was) pretty nonsense.

Also, the use of LM339 gave the ability to use unequal step, as the resistive network may have been designed arbitrarily.
Navigation
Message Index
Next page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod