Push-on LED

The project’s circuit is very simple. It consists of a LED (Light Emitting Diode) connected to a battery in series with a resistor and a switch. The result is a lit LED when the button is pressed.

Objective

This breadboard project is a good starting point for the very beginners.

  • You see how breadboards, resistors, switches and LEDs look like.
  • You understand how breadboard works.
  • You can note some really basic concepts in electronics like polarity, close circuit, Ohm’s law for the resistor value.

The project is also used by advanced makers as warming-up before they continue to more complicated things.

  • It gives the message that the parts (LED, resistor, switch, cables, battery) and equipment (breadboard) have no problem so they can be used in the next project.
  • It boosts you confidence and makes you ready for the next project.

The Schematic

This is the circuit of the project.

pushLED

On breadboard

project-push-on-LED-breadboard

You can see a way to set up the circuit on the breadboard. Remember, there are many correct ways to transfer a circuit on the breadboard.

Notes

  • When the button is pressed, the circuit is closed. Otherwise the circuit is open.
  • As always, we assume that the current starts from the positive battery’s pin, it passes through the resistor and the LED. Current’s destination is the negative battery’s pin.
  • When enough electric current pass through the LED, it makes the LED lit.
  • If too much current passes through the LED, it destroys the LED. A resistor is used to reduce the current. Usually LED can handle 20mA.
  • The resistor’s value selected after some math. Ohm’s law: Current=voltage/resistance. So here, current=9/470=0,019=19mA. That means the 470ohm resistor can protect the LED from being damaged by high current when using battery 9v.