Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [lm3915]

A "Dot/Bar Display Driver". Drives 10 LED's at -3 dB per LED, for a range of 30 dB.

A "Dot/Bar Display Driver" used to create "high rise displays" from an analog input.

Functional Diagram

Functional Diagram from TI's product page.

Typical Application

Typical Application from TI's product page.

See Also

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List of LM Integrated Circuits?

Does anyone have / know of a list of all the LM integrated circuit packages available? The EE stockroom at my university recently reorganized and they cataloged several pages of part numbers without any descriptions of what they do. I was hoping to…
Huckle
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How do I make the LM3914 (LED) Bar-graph driver IC make the LEDs light up brighter?

Like I said in the title, I am using the LM3914 IC to drive a 10 segment LED Bar-graph. The actual subsystem has the signal pin on the IC connected to a capacitor, thus displays the amount of charge the capacitor is holding on the Bar-graph. I've…
TG123
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LM3915 to drive more LEDs / basic questions about PNP transistors in saturation

As a few others here, I'm trying to drive a few (10) LEDs from each output of a LM3915 vu-meter chip. I've read different posts, and it seems the universal recommendation is this great answer. I have, however a few difficulties understanding it in…
niconoe
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Do output LEDs here need resistors?

Consider: Here is the schematic I'm trying to work around. My major question is about the LED bar graph I want to use, on the right side; does it need resistors? I saw three different versions of this microcontroller use ... sometimes with,…
user201301
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Precision Full-Wave Peak Detector component values

so, I am a beginner in electronics...hoping to find some help... here I've found a circuit that I want to use from LM 3915 datasheet..... but the problem is I don't have 0.2 and 0.47 Capacitors... capacitors that I have are 1UF 2.2UF 3.3UF 4.7UF…
Nelson
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Op amp LM324 as pre-amp to LM3915 LED VU Meter

simulate this circuit – Schematic created using CircuitLab I have made a LED VU Meter using LM3915 and added a low pass filter too. Then I've tried a basic op amp circuit using LM324 (inverting and non inverting) to amplify the LM3915's input, but…
Nelson
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What transistor if they are needed do I need to drive 5 blue LEDs on a lm3915 and how should I hook it up?

I am using an LM3915 LED driver in dot-mode. I would like to drive 5 blue LEDs (3.3V forward voltage @ 20mA per LED) per output. What type of transistor should I use to make this happen? And how do i put the transistors in the circuit i was…
Danny
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LM3915 Circuit how to adjust input level?

I have used the circuit diagram that is on page 2 of this datasheet and it works pretty much. I am getting the signal off the output of my computer which has been cut and then feed into my circuit and to the Logitech speakers I run my sound…
Ashley Hughes
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Which precision rectifier should I use for a 60dB LM3915 Vu-meter?

I want to make a 60dB Vu-meter with two LM3915 chips. In the datasheet is recommended to use an external precision rectifier and they give two type of rectifiers: half-wave and full-wave. My problem is that I don't know which should I use. I would…
Marus Gradinaru
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LM3915 VU meter not working properly

I built a LM3915 (waiting for LM3916 to arrive) VU meter based on Sparkfun's tutorial. The problem is, when I plug in the power, only the last LED (LED 10) lights up and LED9 kind of flickers. If I pull pin 9 of the LM3915 to HIGH (+5v) then all of…
theViTALiTY
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Turn a transistor on when any one of nine LEDs is on using an LM3914

I'm wanting to turn a transistor on when any LED from LED2 through LED10 are on with an LM3914 in dot mode. Basically, I want the transistor to be normally off until at least LED2 begins to light (using dot mode). Edit: there is some confusion with…
klcjr89
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using LM3915 to switch relay or motor

I am trying to switch either a 12v motor or a relay with the outputs of a LM3915. I have found an answer on this site about using a pnp transistor on the outputs to switch multiple leds. the circuit - such as this one: What transistor do I need to…
Lloyd_Christmas
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whats the difference between a cascaded band pass filter and a normal band pass filter (Audio visualizer)

simulate this circuit – Schematic created using CircuitLab currently im building an audio visualizer i would like to know what is the difference between a cascaded 2nd order band pass filter and an inverting band pass filter. which type of band…
vijay
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LED bar graph driver with 12 pins?

I wanted to use a 12 LED bar graph with a LED bar graph driver but the the driver I know (LM3914) supports only 10 LEDs. Is there a similar driver IC with more out pins? The purpose is to use the bar graph as a battery voltmeter. DIP package…
Kokachi
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LM3915 questions about data sheet and operation

I am connecting the LM3915 to a PNP transistor to drive LEDs. I have it working in bar graph mode using one LED per output directly (no transistor). On page 7 of the datasheet, it looks like pins 1,10-18 should put out a "0" when in the ON state.…
Tom
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