Maker Pro
Maker Pro

Simple 12v 3amp power supply

Suny

Sep 20, 2016
7
Joined
Sep 20, 2016
Messages
7
I have a 12v 3 amp transformer.how can I supply 3 amp power?? Pls give a simplest circuit.
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
Just connect to the transformer output. You will get 12V AC at up to 3A, the maximum power will be 12*3 = 36W.
What will be using the power?
 

Suny

Sep 20, 2016
7
Joined
Sep 20, 2016
Messages
7
Just connect to the transformer output. You will get 12V AC at up to 3A, the maximum power will be 12*3 = 36W.
What will be using the power?
I need dc power for charge my 12v 9AH battery.
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
To change AC to DC you need a rectifier. The best solution is to use a bridge which can be made from four diodes or a bridge rectifier which is a square block with four connections, two for AC and positive a negative output. You may need a heat sink if running at the full 3A.

To limit the current to a safe level, you could place a bulb in series. I have a tame mechanic friend who saves me headlight bulbs which have one broken filament. An ampere meter whould be advantageous as would a voltmeter. Car alternators are usually set to limit charge to 13.8 to 14V for lead/acid batteries.
 

Suny

Sep 20, 2016
7
Joined
Sep 20, 2016
Messages
7
To change AC to DC you need a rectifier. The best solution is to use a bridge which can be made from four diodes or a bridge rectifier which is a square block with four connections, two for AC and positive a negative output. You may need a heat sink if running at the full 3A.

To limit the current to a safe level, you could place a bulb in series. I have a tame mechanic friend who saves me headlight bulbs which have one broken filament. An ampere meter whould be advantageous as would a voltmeter. Car alternators are usually set to limit charge to 13.8 to 14V for lead/acid batteries.
I also need a full charge mediam and low charge indicator. Would u help me?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
You won't get 3A DC unless you use a switch mode regulator. With a linear regulator the max current without overloading the transformer is a little over 2A.
 

davenn

Moderator
Sep 5, 2009
14,271
Joined
Sep 5, 2009
Messages
14,271
I need dc power for charge my 12v 9AH battery.

what sort of battery ? lead acid, sealed lead acid, something else ?

different batteries require different charging methods
 
Top