12V & 5V Dual power supply Circuit

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Dual power Supply Circuit

Power supply form the basic building block of any electronic circuits and therefore its important to familiarize the DC power supply circuit construction. The above given circuit illustrates a simple approach to construct a dual DC power supply of 5V and 12V from the 230V AC mains supply. The Voltage ranges 5V and 12V are widely used in all kinds of simple electronic circuits, so its meaningful to learn this simple construction. 


The above circuit obtains power from a 230V AC mains supply voltage and fed into a step down  transformer for transforming higher voltage supply to lower one. The transformer TR1 can be of 230V primary ,15V secondary and 1A step down transformer. The stepped down voltage can be fed into the bridge rectifier made of four 1N4004 diodes for the conversion of AC supply to DC one. 

IC regulator pinout

The output from the bridge rectifier was filtered by the capacitor C1 and C2 to offer a steady DC level to the input pins of the regulators used in the above circuit. The DC voltage is then fed in to the IC 7805 which is a 5V regulator and also to the IC 7812 which was a 12V regulator. The output obtained from the 7805 & 7012 are 5V and 12V respectively. A LED D5 was connected through the current limiting resistor R1 for indicate the state of the device.

This kind of circuits are highly useful where two dual range of DC voltages are used to power the operation of a circuit. Varying the voltage regulator IC ‘s 7805 or 7812 with 7806 and 7808 to obtain 6V and 8V as output. But each IC have minimum and maximum voltage requirements, so make sure you build in such a way to meet the requirements. 


Related Designs and Schematics

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Frank Donald

Junior Network Engineer at Tata Communications
Frank Donald is an Electronics and Communication Engineer who loves building stuff in his free time. Video games, blogging and programming are the things he loves most

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24 Comments on "12V & 5V Dual power supply Circuit"

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I have an 18V 2A transformer. will it be ok?


hello, i want to connect a dc motor of 12V,300mA as the load and i have 1A transformer, how can I control the current from 1A to 300mA?

kamal arunashanthi

Hi there I have made this regulator .But I can have very descant 5 v supply but I cant get 12 v with at least 200 ma what is the problem Please advice me.


Hi.. Can I removed C1,C3, 7805,. And can still be functioned?


could it be okey if i use 3 amp center tap transformer?


anyway I sent see the recommended transformer for 15v project 1A


de qualquer maneira mandei vir o transformador recomendado para o projeto de 15v de 1A


Good afternoon the transformer that I used was 12V , I had asked before using the technique of the teachers if it was possible to use it with the specifications

k-CF48-002BR-U09 this is the model but can not find anything about it.


hello I’m having a little problem with the power supply design, I used a 12V transformer in the project, and it worked but began to heat a rectifying diode and the transformer became increasingly hot

Joe Banko

Need to build a pair of dual power supplies. 12V @ 4-5A and 5V @ 10-15A. 5V needs to be as quiet as possible. Are there any circuits like this around? Can I just modify the above circuit with higher power components and heat sinks?

Joe B