Lm3915 Calculator Updated Jun 2026

4.2 Input Conditioning

LM3915 Calculator (updated version) is a specialized online tool designed to simplify the design of audio level indicators and VU meters using the LM3915 logarithmic display driver lm3915 calculator updated

Designing logarithmic LED displays, such as VU meters, power meters, or signal strength indicators, requires precision to ensure the visual output matches the decibel scale of the input signal. The is the industry-standard monolithic integrated circuit designed specifically for this task, driving 10 LEDs in 3dB steps. For quick calculations, is often negligible if R2cap

R2=R1×(VREF1.25−1)cap R sub 2 equals cap R sub 1 cross open paren the fraction with numerator cap V sub cap R cap E cap F end-sub and denominator 1.25 end-fraction minus 1 close paren Using our standard value for R1cap R sub 1 (1200 Ω): For quick calculations

is the current flowing out of Pin 8 (typically a tiny 75 µA to 120 µA). For quick calculations, is often negligible if R2cap R sub 2

While often assumed to be 1.25V, the typical reference voltage is closer to 1.28V, affecting the exact scaling of the logarithmic steps.