# TL431 Calculator – Online Feedback Resistor Calculator

The TL431 calculator is one of the useful tool that can help simplify the design process. It is a popular voltage regulator and has been in use for a long time in many different electronic circuits. It is also called adjustable shunt regulator. This tool can quickly and accurately calculate the values for the two external resistors required to set the fixed output voltage of the TL431.

#### TL431 CALCULATOR TOOL

^Input values for Vo must range from 2.5 to 36V (other input could give invalid output values). Always check for Standard available value of resistor, or you can use customized resistor. Choose higher values of R1 if possible to reduce power consumption.

Always use 0.5%, 1% or 2% tolerance Resistor in voltage regulator feedback circuit to ensure near exact regulated output voltages.

The TL431 calculator tool is an online software program or an online tool that allows users to input the desired output voltage to be taken from TL431 and calculate the required values of the external resistors to achieve that voltage. The tool takes into account the internal reference voltage of the TL431, which is designed at 2.5V.

With the above tool, designers and engineers can quickly and easily calculate the resistor values without the need for complex mathematical formulas or manual calculations.

**The formula for regulated output voltage be:
**

Vo = 2.5 x (1 + R1/R2)

Where,

R1 and R2 are feedback resistor or shunt resistors. Feedback resistor or shunt resistor are there to provide reference voltage (Vref) to the regulator at which the output voltage is to regulate.

Read more about TL431 here

Read datasheet of TL431 here

**Using the TL431 Resistor Calculator Online Tool**

To use the TL431 resistor calculator online tool, simply input the desired output voltage, the value of R1 resistor. The calculator tool will then display the required values of the two external resistors.

**For example,** suppose you want to use a TL431 to regulate the output voltage of a power supply to 12V. The internal reference voltage of the TL431 is 2.5V. Using the TL431 calculator tool, you would input 12V for the desired output voltage. Choose R1 value higher than 1 kilo-ohms, say (1kohm). The voltage regulator calculator tool would then display the required values of the R2 resistors (say 3.8 kilo-ohm).

One of the main advantages of using a TL431 calculator online tool is that it simplifies the design process and saves time. Instead of manually calculating the values of the external resistors, the tool can quickly and accurately provide the values needed to achieve the desired output voltage.

Additionally, the tool can help prevent errors in calculations that can lead to circuit malfunctions or damage to components. By inputting the desired output voltage and the internal reference voltage of the TL431, the tool can ensure that the resistor values are calculated correctly. Whether you are designing a power supply, battery charger, or LED driver, the TL431 voltage regulator calculator tool can be a valuable asset in your design toolkit.