Bookmark a reliable LM3915 Calculator before your next audio project. Your LEDs—and your sanity—will thank you.
To use the LM3915 effectively, you must calculate the values of two external resistors, and R2 , which determine both the Reference Voltage ( VREFcap V sub cap R cap E cap F end-sub ) and the LED Current ( ILEDcap I sub cap L cap E cap D end-sub ) . Reference Voltage ( VOUTcap V sub cap O cap U cap T end-sub LM3915 Calculator
For line-level audio (e.g., 1.228 Vrms = +4 dBu), an input voltage divider is needed before pin 5: Bookmark a reliable LM3915 Calculator before your next
cap I sub cap L cap E cap D end-sub is approximately equal to 12.5 cross open paren the fraction with numerator 1.25 cap V and denominator cap R sub 1 end-fraction close paren is approximately equal to the fraction with numerator 12.5 and denominator cap R sub 1 end-fraction Standard output current is programmable from 1 mA to 30 mA 2. Practical Design Values Reference Voltage ( VOUTcap V sub cap O
An is a set of formulas used to determine the values of external resistors ( R1cap R sub 1 R2cap R sub 2
[ \textAttenuation factor = \fracV_\textref,desiredV_\textmax ]
English