Skip to content

Electronic Project: Build a voltage divider

One usage of resistors is to create a voltage divider.

If you put 2 resistors in series (one after another) in a circuit, like this:

and you measure the voltage drop after the first resistor, you can observe that if the resistors have the same resistance value, for example 1kΩ, the tension after the first resistor is exactly half the original tension.

This is because in a circuit the sum of all voltages around any closed loop must equal zero (this is Kirchhoff’s voltage law).

The difference in voltage measured before the first resistor, and after the second resistor, is ~9V, the voltage provided by the battery.

If you double the resistance of the second resistor, the voltage drop after the first resistor is 3V, while the voltage drop after the second is 6V:

This means that we can adjust the voltage served to a component by using resistors.

The formula to calculate the tension between the two resistors, R1 being the first one linked to the + pole of the battery and R2 the second one, is: V * (R2 / (R1 + R2)).


download all my books for free

  • javascript handbook
  • typescript handbook
  • css handbook
  • node.js handbook
  • astro handbook
  • html handbook
  • next.js pages router handbook
  • alpine.js handbook
  • htmx handbook
  • react handbook
  • sql handbook
  • git cheat sheet
  • laravel handbook
  • express handbook
  • swift handbook
  • go handbook
  • php handbook
  • python handbook
  • cli handbook
  • c handbook

subscribe to my newsletter to get them

Terms: by subscribing to the newsletter you agree the following terms and conditions and privacy policy. The aim of the newsletter is to keep you up to date about new tutorials, new book releases or courses organized by Flavio. If you wish to unsubscribe from the newsletter, you can click the unsubscribe link that's present at the bottom of each email, anytime. I will not communicate/spread/publish or otherwise give away your address. Your email address is the only personal information collected, and it's only collected for the primary purpose of keeping you informed through the newsletter. It's stored in a secure server based in the EU. You can contact Flavio by emailing flavio@flaviocopes.com. These terms and conditions are governed by the laws in force in Italy and you unconditionally submit to the jurisdiction of the courts of Italy.

Related posts about electronics: