10 LEDs VU meter
The LM3915 integrated circuit is designed for applications requiring a visual representation of varying analog voltages. It features a logarithmic display, which is particularly useful in audio applications where signal levels can vary significantly. The IC operates by utilizing a series of ten LEDs that light up in response to the input voltage, providing a clear and immediate visual indication of the voltage level.
The LED current drive is programmable, allowing for flexibility in the design of the circuit. This feature eliminates the need for external current limiting resistors, simplifying the overall circuit design and reducing component count. The adjustable voltage reference integrated within the LM3915 allows for precise calibration of the output display, ensuring accuracy in voltage representation.
The input voltage range of the LM3915 is specified between 12V and 20V, with 12V being the recommended operating voltage. This range makes the IC suitable for various applications, including battery monitoring and audio level indication. The high-impedance input buffer is designed to handle a wide range of input signals, accepting voltages down to ground level and up to within 1.5V of the positive supply. This capability allows the IC to be used in a variety of environments without the need for additional input protection, as it can withstand input voltages of ±35V.
The internal architecture of the LM3915 includes ten individual comparators that are referenced to a precision voltage divider. This arrangement ensures that the output LEDs are activated in a controlled manner, corresponding accurately to the input voltage levels. The result is a reliable and effective means of displaying analog voltage levels in a compact and efficient package. Overall, the LM3915 is a versatile component that can be integrated into numerous electronic designs requiring visual voltage indication.The LM3915 is a monolithic integrated circuit that senses analog voltage levels and drives ten LEDs providing a logarithmic 3 dB/step analog display. LED current drive is regulated and programmable, eliminating the need for current limiting resistors.
The IC contains an adjustable voltage reference and an accurate ten-step voltage divider. The input voltage can vary from 12V to 20V, but suggested voltage is 12V. The high-impedance input buffer accepts signals down to ground and up to within 1.5V of the positive supply. Further, it needs no protection against inputs of ±35V. The input buffer drives 10 individual comparators referenced to the precision divider. 🔗 External reference
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