Introduction: 7805 Voltage Regulator (5V) Module: Quick Tutorial

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In this uncomplicated guide, I'll be sharing the fundamentals of the 7805 voltage regulator, suitable for various projects like those on breadboards, Arduino, and PCB-based electronics.

Supplies

In many instances, diverse power supplies are necessary for my projects, with a frequent need for 5V DC supplies, sometimes more than one. To streamline these projects, setting up small 5V regulator modules proves advantageous.

The 7805 is a fixed output voltage regulator IC belonging to the 78XX family, with variants like 7809 and 7812 providing outputs of 9V and 12V, respectively. Its simplicity lies in its three pins and minimal external components requirement.

Step 1: The Datasheet

The datasheet for the 7805 IC furnishes comprehensive information, encompassing operating conditions, package types, configurations, and recommended operating conditions.

Key points from the datasheet include:

  1. The IC comes in various packages, including TO 220, TO 3, SOT 223, TO 92, and TO 252, among which SOT 223 and TO 252 are SMD, while the others are Through-hole types with long leads.
  2. The recommended input voltage (Vi) range is from 7V DC to 25V DC.
  3. It can deliver an output current of up to 1.5 Amperes.
  4. The IC has three pins/leads: input voltage (Vi), Ground/common, and output voltage (Vo). The common pin, situated in the middle, should be grounded for both input and output.
  5. External components, specifically input and output capacitors, are crucial. The datasheet prescribes a filter capacitor at the input and a filter capacitor along with a low-pass filter at the output.

Due to its nature as a linear regulator, dissipating excess power as heat, the package usually includes a section for attaching a heat sink to manage heat transfer.

Step 2: Gather the Materials

For crafting a simple and compact regulator module, gather the following:

  • A universal PCB or perf board/Vero board/dotted PCB.
  • LM 7805 IC.
  • 10 uF capacitor.
  • 100 uF capacitor.
  • 0.1 uF capacitor.
  • Small wire pieces.

Step 3: Prepare the PCB and Solder the Components

Follow these steps to create the module:

  1. Cut a small piece of PCB.
  2. Mount the IC and solder it.
  3. Position the 10 uF capacitor in front of the 7805 and solder the leads.
  4. Connect the positive lead (longest one) to the first pin of the 7805.
  5. Connect the negative lead (short one) to the middle pin (pin2) of the 7805.
  6. Mount the 100 uF capacitor behind the 7805 and solder.
  7. Connect the positive pin of the capacitor to pin 3 of the 7805 and the negative pin to pin 2 of the IC.
  8. Position the 0.1 uF capacitor parallel to the 100 uF capacitor and solder the leads alongside.

Refer to the attached pictures for further clarification.

Step 4: Wire Connections

Connect the wires for input and output:

  1. Solder a blue wire to pin 2 (middle) of the 7805 and a red wire to pin 1, both for the input.
  2. Solder a black wire to pin 2 (middle) of the 7805 and a red wire to pin 3, both for the output.

Step 5: Circuit Testing

For testing the circuit, connect a 9V battery to its input, and connect the output to a multimeter.

Congratulations, you've created a straightforward 9V regulator module useful for breadboard, Arduino projects, and experiments. Caution is advised for applications with high input voltage, as the IC may generate heat, necessitating the attachment of a heat sink.

Feel free to reach out if you have any questions or need further assistance.