This is the simplest instructable in which I am gonna share you the basics of the 7805 voltage regulator.
In almost all my projects, including breadboard projects, Arduino projects, and PCB based electronics projects, power supplies of different levels does require. Especially 5 V DC supplies are frequently required, sometimes more than one.
So it will be easy to do the projects if we already set up small 5 V regulator modules.
7805 is fixed output voltage regulator IC from the 78XX family. Other varieties are 7809 and 7812 giving outputs 9 V and 12 V respectively. It is easy to be employed because it has only three pins and a few external components are required.
Step 1: The Datasheet
The datasheet of 7805 IC gives the complete information about it including its operating conditions, different types of packages, configurations and recommended operating conditions etc.
The datasheet tells us that
- The IC comes in different packages like TO 220, TO 3, SOT 223, TO 92 and TO 252 out of which SOT 223 and TO 252 are SMD and the others are Through-hole type with long leads.
- Recommended input voltage (Vi) range is from 7 V DC to 25 V DC.
- It can provide output current up to 1.5 Amperes.
- It has three pins/leads input voltage (Vi), Ground/common and the output voltage (Vo). The common pin is the middle one which should be connected to the ground for both the input and the output.
- And the very important thing from the datasheet is that about the external components, the input, and the output capacitors. We should connect, as per the datasheet, a filter capacitor at the input and a filter capacitor and a low pass filter at the output.
- Since it is a linear regulator (the one which drops the unwanted power across its junction as heat), the package usually contains a portion for attaching a heat sink to the heat transfer.
Step 2: Collect the Stuffs
For making a simple and tiny regulator module we need:
- A universal PCB or sometimes called as perf board/Vero board/dotted PCB.
- LM 7805 IC.
- 10 uF capacitor.
- 100 uF capacitor.
- 0.1 uF capacitor.
- Small wire pieces.
Step 3: Cut the PCB and Solder the Components
We can make the module simply following the below steps.
- Cut a small piece of PCB.
- Mount the IC and solder.
- Mount the 10 uF capacitor in front of the 7805 and solder the leads.
- Connect the positive lead(the longest one) to the first pin of the 7805.
- Connect the negative lead (the short one) to the middle pin (pin2) of 7805.
- Mount the 100 uF capacitor in the back of 7805 and solder.
- Now connect the positive pin of the capacitor to the pin 3 of 7805 and connect the negative pin of the capacitor to the pin 2 of the IC.
- Mount the 0.1 uF capacitor parallel to the 100 uF capacitor and solder the leads parallel to the leads of the capacitor.
you can refer the pictures attached to this step for more clarifications.
Step 4: Connect the Wires
Now we have to connect the wires for the input and output.
- Solder a blue wire to the pin2 (the middle one) of the 7805 and solder a red wire to the pin 1, both for the input.
- Solder a black wire to the pin2 (the middle one) of the 7805 and solder a red wire to the pin 3, both for the output.
Step 5: Test the Circuit
For testing the circuit, we need to connect a 9 V battery to its input and its output should be connected to a multimeter.
And finally, we made the simple 9 V regulator module which is useful in the breadboard and Arduino projects and experiments.
Caution: For application in which a high input voltage is involved, the IC may heat up, so we need to attach a heat sink.
Feel free to use the comment box below for the doubts and of course feedbacks.
Thank you :)