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7812 Pin and Circuit Diagram

Very simple circuits using 7812 IC anyone can easily make

7812 is a famous IC which is being widely used in 12V voltage regulator circuits. Truly speaking it is a complete standalone voltage regulator. We only need to use two capacitors, one on the input and second one on the output of 7812 in order to achieve clean voltage output and even these capacitors are optional to use. To achieve 12V 1A current, 7812 should be mounted on a good heatsink plate. Thanks to the transistor like shape of 7812 which makes it easy to mount on a heatsink plate. 7812 has built in over heat and short circuit protection which makes it a good choice for making power supplies. In electronics markets, it 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 Pins Identification

7812 Pin Diagram7812 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 Usage Explained

7812 Basic Circuit Diagram7812 Basic Circuit Diagram7812 In Parallel Circuit Diagram7812 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

Adelusi Tosin2012-07-21 01:11:11

sir i used ic 7812 to charge my 12v 62ah battery through solar panel as the source of power, yet it not charge the battery. Sir, is there any way that i can use to charge this battery throuhg solar cell of 120v dc. Thanks.
Pleased sir kindly anwser to my mail

Mina2012-10-02 17:29:03

Thanks, very useful!
Can I use 24 volt as input, but with a resistor before inserting 24 volt to 7812 to acheive a regulated 12 volt?

CHARY2013-09-09 10:11:10

i want to know how to connect lm7812 to 18volts adaptor

Sanjeev2014-10-29 22:11:03

I want to use LM7812 as 12v LED homelight driver. Can I?

Elektrolord2014-12-02 11:42:10

Before you can use it with 18v you will need to reduce the the voltage by dividing the voltage.

omid2015-02-16 11:16:04

by notice to (W=RI2) and maximum current(1A)
Why does the resistors must be 15 watt ?
Thank you

Sagar Awachat2017-04-11 04:10:14

Dear Sir, Can I use this IC 7812 for input 12 volt 42 Ah DC battery ?

Frederick Gica2017-10-16 16:13:14

I am using step down transformer, 220V in and out is 12v 0 12v and 3ampere as its specifications. Im gonna need a regulated 12v output with still 3ampere current. Can I obtain the same using 7812 regulator when it says it has an output of 12v , 1ampere? If not, how can I obtain 3ampere output?

Audentes2018-01-19 23:33:07

If you want to charge a 12VDC battery you need to supply a higher voltage. Typically 13 to 15 VDC. Think of this as a balance scale. You want to transfer, water, for example, from one side to the other. If the levels are equal, no water will transfer. Hence, if a 12 volt battery is on one side, then 12 volts on the other will result in no transfer to the battery.

Hugo2019-11-13 09:36:57

For load balance resistors substitute diodes and accept the 0.7 voltage drop. Use LM7815 and external control resistors is fine voltage control for "12 volt" lead acid battery charging.

Steve2020-11-27 05:59:32

sir can i use l7812cv in place of lm7812?
Genius: @steve yes you can use l7812cv instead. They are both essentially same and function in the same way,

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