1 Simple LED circuit

This circuit is very simple to make and requires only basic knowledge in electronics. We need only 3 main electronic parts, the LED, resistor and battery or dc supply.

Materials:
1- LED  (red , yellow or orange)
1- 200 ohms resistor
4 -1.5V cell (AAA or similar)
1-breadboard (optional)
1-battery holder for 4-AAA cells (optional)

Materials pins and diagram

LED pins and symbol

Resistor

1.5V AAA cells

Simple circuit schematic

LED requires around 20mA current to emits a good light. Standard red led requires 2V voltage drop or forward voltage to turn on. Since we know that our battery voltage is 6V, we can solve the value of resistance
which is equal to:
Resistance = (Vbat-Vled)/Current = (6-2)/20mA = 200 ohms

Note: You can use led resistor calculator If you are planning to use different type of LED ,battery  voltage, and different current.