I know exactly how that goes sometimes!!!
Someday's everything just works perfectly, and someday's the very same circuit with the very same configuration and test will give me wonky results!!!
Electronics is weird like that at times. 😉
jer 🙂
Someday's everything just works perfectly, and someday's the very same circuit with the very same configuration and test will give me wonky results!!!
Electronics is weird like that at times. 😉
jer 🙂
Question. I'm using a lm3915 for a Vu meter for my amp but I cannot get it to work. I'm using very thin wire, 10 connected together and cant think of the name, but it's also quite long. Could this be the problem. I think the lm3915 uses 20ma per Led and I'm wondering if the length and distance is the problem.
You are using 10 Lm3915's?
Do you have them in Dot mode or Bar mode?
I love those chips I used to have a 30 LED setup once.
jer 🙂
Do you have them in Dot mode or Bar mode?
I love those chips I used to have a 30 LED setup once.
jer 🙂
Never mind. I had the led's configured wrong. So much time wasted troubleshooting ...
No I never got it working. I'm using long thin wire to connect to the output of the lm3915. I redid the hole thing with a exact bread board replica and it will not work. In the data sheet it says to use a 2u2 uf cap if Led leads are longer than 6mm, and I'm using thin wire probably around 12in and 8 inch for each chip.
The wire size shouldn't be causing any issues, I used 12 inch lengths of 30ga. wire wrap wire to feed all of my 30 LED's.
I do remember that of the stock of chips I had some of them didn't work, I don't know why.
I think I remember burning one or two of them out as well, but again I forget exactly what happened as this was 14 years ago and i don't have the circuit I made anymore.
I was using the LM3914 linear step version.
I used it as a output voltage indicator for a regulated 0v to 15v 30amp power supply that I made out of a UPS power transformer that I had.
I just followed the example found on the data sheet, it was confusing on how to setup the Input and Reference voltages and Dot/Bar modes, but I did finally get them to work.
Even though it worked for what I was using it for, I had found that the internal resistor divider for each step was not very accurate, but it worked okay.
The input voltage must be a DC only signal so you need to run your signal through a Full or Half wave rectifier circuit in order to get a voltage representation of your signal level.
Here a bunch of circuits for the LM3914,the LM3915 is identical except its internal resistor divider as set up for 3db steps instead of linear steps,
https://www.google.com/search?q=LM3...its%2Fstereo-power-meter-l13440.html;1186;884
This is the data sheet for the LM3914,
http://www.ti.com/lit/ds/symlink/lm3914.pdf
jer 🙂
I do remember that of the stock of chips I had some of them didn't work, I don't know why.
I think I remember burning one or two of them out as well, but again I forget exactly what happened as this was 14 years ago and i don't have the circuit I made anymore.
I was using the LM3914 linear step version.
I used it as a output voltage indicator for a regulated 0v to 15v 30amp power supply that I made out of a UPS power transformer that I had.
I just followed the example found on the data sheet, it was confusing on how to setup the Input and Reference voltages and Dot/Bar modes, but I did finally get them to work.
Even though it worked for what I was using it for, I had found that the internal resistor divider for each step was not very accurate, but it worked okay.
The input voltage must be a DC only signal so you need to run your signal through a Full or Half wave rectifier circuit in order to get a voltage representation of your signal level.
Here a bunch of circuits for the LM3914,the LM3915 is identical except its internal resistor divider as set up for 3db steps instead of linear steps,
https://www.google.com/search?q=LM3...its%2Fstereo-power-meter-l13440.html;1186;884
This is the data sheet for the LM3914,
http://www.ti.com/lit/ds/symlink/lm3914.pdf
jer 🙂
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Hey Gerald, here is my completed final project. It consists of 2 lm3886's, a few lm317's, and a vu meter using 2 3915's. Thanks for all the help.
An externally hosted image should be here but it was not working when we last tested it.
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