12V to 5V 3A DC converter step down Regulator

My friend bought a digital camera that can take pictures and videos as well. But he tell that it have restrictions is available not long the battery runs out. He did use an external battery, but the size 5 volts not had to modify the battery lead acid 12 volts reduced pressure down to the 5 volts.

OR other case. If you want the power supply for digital circuit testing or use. It’s like if you have voltage 5 volt 3amp power supply 12V directly from the battery, then it must have a lower voltage to 5V and a current sufficient. I would recommend this circuit. The principle was simple looking device for sure.

I has 12V to 5V 3A DC converter step down Regulator circuit come to deposit. In sometimes friends have power supply 12V 3A , but want Voltage 5V 3A for digital Circuit. This circuit can meet the demand of friends get , by it uses normal electronic part and have 7805 integrated circuits perform to control Voltage 5V Regulate alone it gives current get just 1A. then must have an assistant is transistor MJ2955 perform enlarge current tallly go up be 3A besides.

When be born over load or shot circuit as a result still have LED1 bright warn with. And still make Q2 – BD140 work cause Q3 – MJ2955 stop work with. The circuit then safe have no a problem friends may like this circuit. Because the equipment seeks easy , build not difficult too.


I have old GPS, usually I use it in my car. We need to have DC to DC converter circuit that can reduce voltage 12V to 5V at current more than 2A.
Which circuit diagram can make this. I like it that need buy some parts since I have also in my stores.
12V to 5V DC supply on my cay for GPS
As Figure 2 I assemble them on universal board

Other similar circuits.

  1. Microprocessor dc regulator supply 5V 3A by LM323K
  2. 5V 3A switching power supply by LM2576
  3. LM2673 -5V 3A Switching Voltage Regulator
  4. Power supply 5V 2A by IC 78S05
  5. Top Linear power supply regulator 5V 5A with 7812 and LM723

11 thoughts on “12V to 5V 3A DC converter step down Regulator”

  1. I had a typo on my previous request. On circuit 12V to 5V 3A DC converter step down Regulator, shows r1 as 0.22 ohms, what is the correct value?

  2. I would like of schematic diagram circuit of voltage regulador that can input with voltage between 6V and 13V and has constant 5V output for 1A

  3. what wattage are the resisters? at 500ma R5 melted. For bd140 I used nte242, for bc556 I used nte232 for mj2955 I used nte332. I know nte332 needs a big heat sink …what about the rest?

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