Pin 9 is the mode pin. And then we can calculate resistor R1. How we go about computing this is this: We do and show the math below so that there’s a exact relationship between the voltage and the LEDs lit on the bar graph. As the resistance increases, the voltage increases, so the LEDs begin turning on.

Uploader: Brasar
Date Added: 20 August 2005
File Size: 25.5 Mb
Operating Systems: Windows NT/2000/XP/2003/2003/7/8/10 MacOS 10/X
Downloads: 14261
Price: Free* [*Free Regsitration Required]

According to the datasheet, if you are not using LEDs with leads that are 6″ or longer, you can connect this pin directly to ground.

How these resistors are determined are given by the formulas given by the manufacturer. The same voltage that powers the chip can be used for V LED We do not have to connect current-limiting resistors to the LEDs because the R1 resistor functions as the current-limiting resistor.

Basically, it can simulate bar graph results. And then we connect pin 2, V -to ground.

How to Build an LM3914 Dot/Bar Display Driver Circuit

At 5V, all 10 LEDs turn on. Using 10mA, resistor R1 calculates out to be 1. An LED bar graph is a device that can be a visual indicator of voltage output. In this case, all the Diwplay will be off. It will remain in our system until you withdraw your consent.


Pin 9 is the mode pin. Bar mode is a mode in which if full voltage is going to the chip, all 10 LEDs will be lit up. The advantage of using LM is that it requires minimum hardware and can be easily set up.

Since we are monitoring V here, the low reference voltage pin 4 is set at 0V and the high reference voltage pin 6 is set to 5V. This IC eliminates lm391 need for microcontroller and programming visplay also reduces the hardware required to control 10 LEDs.

LM Dot/Bar Display Driver IC | NightFire Electronics LLC

Meanwhile, in bar mode, dixplay eight LEDs will be on. As the resistance increases, the voltage increases, so the LEDs begin turning on. And then we can calculate resistor R1. At 3V, 6 LEDs turn on. We GRobotronics will add your email address to a special mailing list for this product. LED bar graphs are used often in VU meter circuits, in lm39144 the LED bar graph can be lit up in proportion to the amount of voltage a device is outputting.

This circuit can be a building block to build a number of other circuits. The LM is very easy to apply as an analog meter circuit. Complete Technical Dislay can be found at the LM datasheet given at the end of this page.


How to use a LM? The pinout of the LM is shown below. In this circuit, we’re going to use the LED bar graph to show the level of voltage that a potentiometer has.

This establishes power to the chip. The IC can operate in two different modes, one is the dot mode and the other is bar mode.

Powered by GRobotronics Team. The potentiometer we will use can really be of any value. If you continue, we assume that you agree to receive cookies from this dot/bad.

So you can use whatever you have. In dot mode the mode pin pin 9 has to be left floating, in this mode only one LED will be turned on based on the input voltage. Pins 1 and are the output pins.