LED power supply with LM7805 integrated circuit

LED power supply with LM7805 integrated circuit

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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:

Placing components on breadboard

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:

Download the manual and electronic diagrams

To carry out this project in your own laboratory, download the manual here, electronic diagrams and placement of components on breadboard in .fzz format (Fritzing design) by here.

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