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From the references to other threads, you're NOT connecting the LM3914 to +18 V, but to +/- 9 V. That's not the same. As you've seen for yourself, it works when connected to 0 and +9 V, which is exactly as it should be.
What Benta said.If you're connecting the LM3914's GNDs to -9V, the SIG input would now appear to be at +9V to the LM3914, so all LEDs on.If in bar mode 18V would also give a dissipation problem when nearly all the LEDs are on.Is there a good reason why it can't be powered from the 0V and +9V.
Well my reasoning is that one battery will drain sooner then the other ¿ or ?
I was disappointed to find that the DIP packaged version had been discontinued and it was SMD only from the large vendors, DigiKey Mouser etc.
I recently had a project where the LM3914 looked like a good candidate, I was making a VU meter for a small audio amplifier. I was disappointed to find that the DIP packaged version had been discontinued and it was SMD only from the large vendors, DigiKey Mouser etc. That put me in the realm of suppliers on ebay and the like where i am always wary of counterfeit chips. Were you able to find a reliable source for good DIP packaged chips, or did you use the SMD versions?
I don't think I would bother with LM3914. Nowadays, I'd use an MCU, or if I really had to go analogue: 3 quad op-amps/comparators, a cheap reference, such a TL431 and a butt-load of resistors.
Quote from: Zero999 on July 12, 2021, 02:44:27 pmI don't think I would bother with LM3914. Nowadays, I'd use an MCU, or if I really had to go analogue: 3 quad op-amps/comparators, a cheap reference, such a TL431 and a butt-load of resistors.Hi,I still have some LM3914 laying around so it was logical that I wanted to use them.Using op amp instead of LM3914 means 1 op amp for every Led and so I would need 10 additional op amps for my 10 LED bar. Lots of resistors and lots of space. Anyhow interesting idea for a future project.
May I ask which MCU ¿?Thanks Rainer
Quote from: NHSA on July 12, 2021, 05:08:34 pmQuote from: Zero999 on July 12, 2021, 02:44:27 pmI don't think I would bother with LM3914. Nowadays, I'd use an MCU, or if I really had to go analogue: 3 quad op-amps/comparators, a cheap reference, such a TL431 and a butt-load of resistors.Hi,I still have some LM3914 laying around so it was logical that I wanted to use them.Using op amp instead of LM3914 means 1 op amp for every Led and so I would need 10 additional op amps for my 10 LED bar. Lots of resistors and lots of space. Anyhow interesting idea for a future project.The TL084 & LM324 have 4 op-amps, so 3 ICs would give 12 op-amps, 10 of which can be used as comparators, with the remaining two as op-amps for the rectifier. They're much cheaper than the LM3914.QuoteMay I ask which MCU ¿?Thanks RainerAny MCU with an ADC input and at least 10 output pins for the LEDs. Here's a link to a bargraph meter with 20 LEDs, using the PIC16F686.http://www.electronics-lab.com/project/bargraph-voltmeter-0-5v-dc-range-pic16f686/
Quote from: Zero999 on July 12, 2021, 09:51:03 pmQuote from: NHSA on July 12, 2021, 05:08:34 pmQuote from: Zero999 on July 12, 2021, 02:44:27 pmI don't think I would bother with LM3914. Nowadays, I'd use an MCU, or if I really had to go analogue: 3 quad op-amps/comparators, a cheap reference, such a TL431 and a butt-load of resistors.Hi,I still have some LM3914 laying around so it was logical that I wanted to use them.Using op amp instead of LM3914 means 1 op amp for every Led and so I would need 10 additional op amps for my 10 LED bar. Lots of resistors and lots of space. Anyhow interesting idea for a future project.The TL084 & LM324 have 4 op-amps, so 3 ICs would give 12 op-amps, 10 of which can be used as comparators, with the remaining two as op-amps for the rectifier. They're much cheaper than the LM3914.QuoteMay I ask which MCU ¿?Thanks RainerAny MCU with an ADC input and at least 10 output pins for the LEDs. Here's a link to a bargraph meter with 20 LEDs, using the PIC16F686.http://www.electronics-lab.com/project/bargraph-voltmeter-0-5v-dc-range-pic16f686/Hi Zero999,Thanks. I will think about the opamp solution which is somthing new, but now ¿ where is the fun by buying ready made stuff ? As I mentioned earlier it is also a question of the size of the ready made enchilada.Thanks again and regardsRainer