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How to use a LM? Submitted by webmaster on 27 September Since the reference voltage is 5V and there are 10 LEDs, each 0. Or for every 0. With varying voltage, we get varying LEDs lit. If you are using LEDs with pins 6″ or longer, then you would place a capacitor in parallel to this pin. The formulas and math of how this was calculated was shown above.

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If you are using LEDs with pins 6″ or longer, then you would place a capacitor in parallel to this pin. Since the reference voltage is 5V and there are 10 LEDs, each 0. So you can use whatever you have.

LM Dot/Bar Display Driver Pinout, Datasheet, Features & Equivalent

In this circuit, we’re going to use the LED bar graph to show the level of voltage that a potentiometer has. This IC eliminates the need for microcontroller and programming and also reduces the hardware required to control 10 LEDs. Basically, it can simulate bar graph results.

For example, if dispay measuring battery power in a circuit, the LED bar graph can project the strength of the battery life.

This is the signal pin. It may vary by a few tenths of a volt depending on the tolerane of the resistors and if you used the same exact resistances offered. At 2V, 4 LEDs turn on.


How to use a LM? You can replace the potentiometer so with any type of sensor measurement to measure anything. At 5V, all 10 LEDs turn on. Using the resistor R1 value we calculated before of 1.

LM Dot/Bar- Display -Driver- IC

Pin 9 is the mode pin. The below circuit is a typical application circuit for LM By varying the potentiometer, we change the voltage fed into the pin and this changes the LEDs that bae turned on in the LED bar graph. An LED bar graph is a device that can be a visual indicator of voltage output.

And then we connect pin 2, V -to ground. Pin is the mode pin. According to the datasheet, a good current to flow through the LEDs is 10mA.

In the above example we have used a ohm resistor as Rl and hence displaay current through each LED will be around 25mA, you can modify the value as required.

LM3914 Dot/Bar Display Driver IC

At 4V, 8 LEDs turn on. If the pin is connected either to ground or is left unconnected floatingthen the chip is in dot mode. The less voltage, the less LEDs on.


This circuit can be a building block to build a number of other circuits. Or for every 0. As we turn the potentiometer so that its resistance, and, therefore, voltage increases, the number of LEDs that light up on the bar graph increase proportionally. As the resistance increases, the voltage increases, so the LEDs begin turning on. This is because the IC output pins can only sink current and cannot source it.

How to Build an LM3914 Dot/Bar Display Driver Circuit

Depending on the its resistance affects the voltage directly. This is the pin that allows us to have the LM in bar mode or in dot mode.

In this case, all the LEDs will displzy off. As we increase voltage, more LEDs turn on. Next in pins 6,7, 8, we place our biasing resistors R1 and R2 to obtain the current of 10mA.

We place a toggle switch on this pin so that we can switch between the 2.

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