In this tutorial, you will learn how to simulate voltage level indicator circuit using the LM3914 Dot/Bar graph Driver. The LM3914 is a monolithic analog controlled LED driver IC as well as its counterpart the LM3916, the difference between the both is that the LM3916 gives a logarithmic output scale, while the LM3914 gives a linear output scale, this makes the LM3916 suitable for volume unit (VU) meter. The IC can drive 10+ LEDs. One interesting thing about the IC is that it can be configured into either a dot output mode or a bar graph output mode.
Parts required for voltage level indicator circuit
To carry out the simulation of the voltage level indicator circuit Proteus, you must have installed Proteus in your computer, if you do not have Proteus on your computer, you can download it from my page. Follow the instruction on how to install it and install get it installed on your computer. Open the software and pick the following components below to make the circuit for the simulation.
- 12 volts battery (active)
- 3 LED-RED (active)
- 3 LED-BLUE (active)
- 3 LED-YELLOW (active)
- 1 LED-GREEN (active)
- 10K Potentiometer (active)
- 2.2K Resistor
- 18K Resistor
- DC Voltmeter
- SPST Switch (active)
Note that the active components must be selected to give real-time simulation. See full video of the simulation below
This circuit can be applied in so many places. In any device that gives information about the voltage signal level, like in volume systems, inverter system, battery charger circuits, avionics, telemetry systems, etc.
Though the LED used in this circuit simulation is individual LEDs, however, we have volume meter (VU) LED module that is sometimes used instead of individual light emitting diodes. The volume meter light emitting diode module is a just a pack of 10 light emitting diodes that are embedded together inside translucent pack having different colors to indicate different voltage levels. The image of the volume meter LED module is shown below.
For further study, check out these tutorials