The only problem is there is a “blip” across all led’s on the ULN output at power on. With the component values shown, this circuit has a full-scale sensitivity of 10V and provides a LED-drive current of 16mA. You have the choice: The pinout of the LM is shown below. In this case, all the LEDs will be off. 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.

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At 5V, all 10 LEDs turn on. If a slowly rising input voltage is now applied to pin 5 of the IC, the following sequence of actions takes place. As the resistance increases, the voltage increases, so the LEDs begin turning on.

LED ‘Graph’ Circuits | Nuts & Volts Magazine

If, for example, a total resistance of 1k2 equal to the paralleled values of R1 and the 10k of the ICs internal potential divider is placed across pins 7 and 8, the 1. Their scales can easily be given any desired shape.

They might well be real comparators, the symbol is the same. This circuit can be a building block to build a number of other circuits.

Method of obtaining a bar display with graphh operation and minimal current consumption. In the LM, the resistors are weighted in semi-log fashion and produce a display that is specifically suited to VU-meter applications.

The pinout of the LM is shown below. At 4V, 8 LEDs turn on. To calibrate the above circuit, first set the supply to 15 volts and adjust RV1 so that LED 10 just turns on. In practice, the IC can be powered from DC supplies in the range of three to 25 volts, and the LEDs can use the same supply as the IC or can be independently powered; this latter option can be used to keep the IC power dissipation at a minimal level.


With the component values shown, this circuit has a full-scale sensitivity of 10V and lk3914 a LED-drive current of 16mA.

An alternative variable-range 1. If 5 LEDs are lit, this could mean it’s at half strength. Figure 5 shows the connections for making a variable-range 1. Dot mode only lights up a single LED at a time. Post as a guest Bzr. According to the datasheet, a good current to flow through the LEDs is 10mA.

For example, if we replace the potentiometer with a resistor and photoresistor in series, we can build a light-sensing device and then the LED bar gdaph and light to show the light intensity that the photoresistor is detecting.

There may be tricks you can play with the reference inputs to simplify the analog input “logic”, I haven’t followed your links and studied it.

Bar-Graph Voltmeter Range 0 To 10V Using LM3914 & 10 LEDS

Just as the SSR’s would that I provided references to yesterday. The IC can be made to give a bar display by wiring pin 9 directly to pin 3 positive-supplyor — if only one IC is used — can be made to give a dot display by leaving pin 9 open lee or ler pulling it at least mV below the pin 3 voltage value. The connections are similar to those of Figure 14except that pin 9 is taken to pin 3 on each IC, and a R current-limiting resistor is wired in series with each LED to reduce the power dissipation of the ICs.


In this case, all the LEDs will be off.

How to Build an LM3914 Dot/Bar Display Driver Circuit

They are moderately complex but grzph versatile nar, housed in pin DIL packages and each capable of directly driving up to 10 LEDs in either the dot or the bar mode.

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I guess the LM must have all outputs low when it starts?

Depending on the its resistance affects the voltage directly. When the input voltage reaches the 0.

LED Bar Graph Pinout, Features, Connections & Datasheet

Assume that the IC logic is set for bar-mode operation, and that the 1. But when the output is not active then it remains open and floating.

The only problem is there is a “blip” across all led’s on the ULN output at power on. rgaph

Finally, the LM has a semi-log scale that spans 23dB, and is specifically designed for use in VU meter applications.