View Full Version : How to make a dual power supply circuit

03-02-2007, 12:59 PM
I am trying to make a mannualy robot and want to make a dual power supply .I have a D.C 24volts supply with two terminals +ve and -ve giving 24 volts output ,but i really want to split it into D.C +12V and -12V supply as the robot needs to be reversed also ,The current rating maximum should be about 1.5A maximum .I want to design a simple circuit using only capacitors and resistors for obtaning the dual power supply and i am unable to do the calculation on my own .Please help me to design the power supply
Thanking you

03-02-2007, 01:48 PM
Dude i think u have no idea what u are talking about , rather than having fun at your expense ill ask you to do a little googling before you ask such question.

03-02-2007, 07:01 PM
hey what you are building some contraption robot :lol: :lol: :lol:
when you can do same thing in more easy way

any ways you can get -12 volt by using lm7912 but at 1.5 A they will get blown out

03-04-2007, 08:49 PM
I have googled the topics but was unable to find conclusive answers they were all using compilicated circuits ,i really wanted a simple power supply, even excluding the LM7812 and the LM7912 ,i know these are good ic's but i was just asking that is it practical to make a bit high current power supply without these things .Thank you very much for your answers .

03-05-2007, 01:08 AM
Well...you can use a potential divider consisting of 2x Auto headlamp bulbs in series across the +v and -v, Centertapped and in parallel with 2x 25W zener diodes in series wiith thw same +v and -v, in parallel with some 2x 10000uFd capacitors wired in the same manner as the above components. The center tap will be ZERO, Anode +V and the cathode -V.

...and Good Luck :D

Well, you wanted a SIMPLE solution.....

03-05-2007, 05:24 AM

If you just need to reverse the direction of the motors, you DO NOT NEED a Dual power supply.

For a manually controlled robot, you just need a DPDT switch, with center-Off position for each motor.
This kind of switch can be easily available in electronics parts shops.
Its handle (rocker switch) has 3 postions.
The center position disconnects everything.

Now your next step should be to design a circuit/connections using this DPDT switch to change the polarity of voltage across your motor.

Please dont ask for that connection diagram, beacause you will really loose the joy & satisfaction of designing the connections yourself.

If you want, do look up DPDT switches on google.

(PS. In this case you will need a single 12V supply. I think DPDT it is much better and hassle free than converting a single to dual supply.)

(PS2- when you buy the DPDT, try to get spring loaded DPDT, which will give you the Joystick effect while controlling your robot..--called Sprin-center-return sometimes...)