 # LED power supply with LM7805 integrated circuit

#### What it is?

The project is intended for children between 10 and 15 years old. It shows the power supply of an LED using the integrated circuit as a stabilizer LM7805.

The assembly aims to learn the basics in electronics, in a way that is as interactive as possible, especially on the power supply side of electronic circuits.

#### Necessary components

1 x Electronic test board + connecting wires
1 x C1 = 100uF
1 x C2 = 10uF
1 x LM7805 (stabilizer)
1 x LED
1 x R1 = 120 Ohm
1 x Contact terminal
1 x R2 = 60 Ohm ~ 68 Ohm
1 x R3 = 6.6 Ohm ~ 10 Ohm
2 x LED

For a better understanding of the functionality of the circuit and to achieve this assembly on the breadboard we will need electronic scheme presented below:

#### Issue 1

We have the following data:

1. Stabilizer output voltage = 5V
2. Input voltage (Wine) = 9V
3. Voltage drop on LED = 1.6V
4. LED current consumption = 30mA

##### How do we check if the value of resistance R1 is correct or not?

Applying the following calculations:

#### Problem 2 - Lighting two LEDs using the LM7805

We have the following data:

1. Stabilizer output voltage = 5V
2. Input voltage (Wine) = 9V
3. Voltage drop on LEDs = 1.6V + 1.6V = 3.2V
4. LED power consumption = 30mA
##### What is the value of resistor R2 for the circuit below?

A variant of location of components on breadboard for problem 2, is presented below:

#### Problem 3 - Lighting three LEDs using the LM7805

We have the following data:

1. Stabilizer output voltage = 5V
2. Input voltage (Wine) = 9V
3. Voltage drop on LEDs = 1.6V + 1.6V + 1.6V = 4.8V
4. LED power consumption = 30mA
##### What is the value of resistor R3 for the circuit below?

A variant of location of components for the breadboard for problem 3, is presented below: