Lm3915 Calculator Updated Review

Furthermore, selecting resistor values for R1 and R2 to get a specific LED brightness and a specific input range (e.g., 0dBm at 0.775V RMS) required solving simultaneous equations involving LED current and reference current.

You have a 9V battery. Enter 9.0 .

R_LED = (Vcc - Vf_LED) / I_LED

Older calculators never did that, leading to many melted chips. Let’s walk through a real-world example. Assume you are building an audio distortion meter that needs to read from -20dBV (0.1V RMS) to +3dBV (1.4V RMS). lm3915 calculator updated