That’s why I’ve updated the – to turn datasheet math into instant, visual results.
is typically 10 times the current flowing out of the REF OUT pin) .
Older calculators never did that, leading to many melted chips. lm3915 calculator updated
Do you prefer (thermometer style) or Dot mode (single moving dot)?
Properly implementing your calculated values requires correct wiring of the control pins. That’s why I’ve updated the – to turn
One of the LM3915's most elegant features is that a single resistor ( Rset ) sets the current for all ten LEDs. This eliminates the need for individual current-limiting resistors for each LED.
For example, if you choose R1 = 1.2 kΩ and R2 = 3.6 kΩ, your Vref would be approximately 5.0V, meaning the 10th LED (full scale) would light up when the input signal reaches 5V. Do you prefer (thermometer style) or Dot mode
tantalum or electrolytic capacitor placed physically close to Pin 3 (
This calculator uses the standard formula Iled = 12.5 / R1 to calculate the LED current based on the resistor value and vice versa, as defined in the LM3915's datasheet.