7805 Pins Diagram

7805 Voltage Regulator Circuit

I have attached an image of 7805 IC to describe its pin configuration setting. In addition to that I have also attached a small fully working voltage regulator circuit diagram with this tutorial. The two capacitors used in the voltage regulator circuit are not mandatory but they are good to maximize voltage regulation. The capacitor values I have used in this circuit are not written on stone, you can change them slightly.
7805 IC has a thermal shutdown feature to protect the IC in case of overheating so it should be safe to use 7805 without a heatsink plate for less than 200mA load. However should your load cross 200mA, you should consider using a heatsink plate. Heatsink plate should be large enough to bring 7805 heat to such a level that you can comfortably touch it.
7805 is a linear voltage regulator, so it is not very efficient and it has drop out voltage problem. It wastes a lot of energy in the form of heat. You can calculate the wasted energy with following formula. This formula will also help you to estimate the size of heatsink plate you will require to disperse amount of heat generated by 7805.
(Input Voltage – 5) x Output Current
Suppose the input 15 volt and output current you require is .5 Amp by using above formula
(15 – 5) x 0.5
=10×0.5
=5W
5W energy is being wasted as heat and you will need a decent sized heatsink plate to disperse this heat to ease your 7805. On the other hand the energy you are actually using is only (5 x 0.5Amp) =2.5W. So you are going to waste twice energy then you are actually utilizing. On the other hand, if give your 7805 9V as input at the same amount of load, only 2W { (9-5) x 0.5 } energy will be wasted as heat.
So the conclusion is, the higher the input voltage get, the less efficient your 7805 will be. You should try to stay slightly over 7.5V. However don’t get bellow 7.5V as your 7805 won’t give a regulated output if the input voltage get bellow 7.5V. If your input voltage are less than 7.5 like 6V then you should consider using a low dropout voltage regulator such as LM2940. Pin connections of LM2940 are also same like 7805.
You don’t need extra components to create a 5 volt regulated power supply with 7805. However it is a good idea to use one capacitor on input and one on output pins to make output voltage smooth but then again, they are not necessary to be used.
As per specs, 7805 input voltage should range between 7.5V to 35V but personally I haven’t tried more than 15V yet. Maximum output current of 7805 is 1A with a good sized heatsink plate. If you are planning to use more than one 7805 in parallel to get more current (above 1A), you better try to put .5Ohm (10W) resistor on the output pin of each transistor to cover the slight voltage difference as technically no two 7805 can provide exactly same output voltage.

7812 circuit diagram

In electronics markets, 7812 is sold under various names such as 7812a, 7812act, 7812t and lm7812. All of them are almost identical with a little to no differences at all. 7812 input voltage range is 14V to 35V. Exceeding the voltage range may damage the IC. Given bellow is 7812 pin diagram to make the pinout connections clear in case you want to do some experiments.

7812 pin diagram

If you hold upside down (pins up) and the IC number is facing you then the left pin will be the voltage regulator output, the center pin will be ground and the right pin will be the voltage input pin. Under my experience, the maximum safe current you can get from one 7812 IC is 1A. If you need more power then there are a few ways to do so.
More than one 7812 can be used in parallel in order to achieve more than 1A current but output voltage of each 7812 can slightly vary resulting in unbalanced load on all of them. This can result in load balancing issues and can damage the IC carrying most current. However there is a way to overcome this problem. I have given bellow a schematic diagram in which two 7812 ICs are attached together and both of them are carrying almost equal load. At least the current difference is not too much to damage any IC.

7812 in parallel circuit diagram

Please note that in this circuit diagram, I have used resistors for load balancing purpose so the output of this voltage regulator circuit may slightly inaccurate. Both resistors should be minimum 15 Watt or above. If you don’t find such resistors in your area then you can make them using 32 gauge or thinner copper wire. This parallel 7812 circuit will provide 12V and approximately 2A current. You can increase number of 7812 but each additional 7812 will require a resistor on its output.
Following is the link to a simple but complete power supply circuit diagram developed using 7812.

Voltage Regulator Circuit

Remote controls also throw infrared IR light which you cannot see but your cell phone camera will capture it. Just press any button of your remote control and see the that portion of your remote control where a small LED bulb is present, normally it is front side of your remote control. Now if you see it through the camera’s LCD display you will see that the IR LED bulb in front of your remote control lights up if you press any button of you remote control. Imagine if you have a lot of such bulbs grouped together and you light them up then your camera will be able to see clearly even without the visible light. Human eyes cannot see infrared IR light therefore infrared light doesn’t disturb sleeping persons as well.

In simple words, many infrared IR LEDs grouped together to throw good amount of IR light are called Infrared/IR Illuminator. You can easily build an infrared illuminator yourself at home with a little effort. You should have basic electronics knowledge on order to attempt this simple IR illuminator project.

Here is the infrared IR circuit diagram.

Infrared IR Circuit Diagram

There is nothing difficult in this circuit. I have used 68Ohm and 1 Watt resistors in this circuit diagram. The Infrared LEDs are easily available from every electronics store. Some users have reported that they have successfully used 5 LEDs in per series which made the LEDs a little brighter however it is up to you, you can do some experiments by changing number of LEDs.

For fitting purposes, I used general wiring board available in the market and fit the Infrared IR LEDs in such a way that they make two circles. A large circuit and a small circle inside the large circuit. This gave the Infrared light a torch like effect by concentrating IR Infrared Beam in a small area. After the fitting, I cut the outside of the wiring board in a round shape and fit it inside an old Torch’s body. Now I use it as an infrared Headlight in my backyard along with my security camera.

Voltage Regulator Circuit Diagram

Here goes the parts list.
1. 240V to 15V 1.2A Transformer
2. 4 pieces of IN4001 (You can use a bridge rectifier as well)
3. 220uF 25V Capacitor
4. .1uF 25V Capacitor
5. 7812 IC (Integrated Circuit)
6. A heat sink plate for 7812 IC
7812 is a very good voltage regulator integrated circuit (IC). It is cheap but efficient, that is why I selected it for this regulator circuit. 7812 Pin2 connections are also explained in my regulator circuit diagram. You can see that Pin 1 is input, Pin 2 is Ground (which is often –V) and Pin 3 is output. It is very simple to understand 7812. The 220uF 25V capacitor is used as a buffer to cover frequency gap. The second capacitor is used as an extra filter. IN4001 rectifiers are used to convert AC current into DC current. Transformer is used to convert 240V AC into 15V AC. If you have 110V mains then you can use a 110V AC to 15 AC transformer.
I have successfully used this voltage regulator circuit to power up my ADSL modem. In fact, the ADSL modem was restarted every one hour or so with its original power supply but after I replaced it with this voltage regulator circuit, the modem is never restarted by itself. Any electronic device which requires 12V 1A power can be powered by this circuit so feel free to use it. You can post your questions and comments in the comments section bellow.