0-30V Stabilized Power Supply

[mrk86]

Demonstration of my Power Supply.

Video: http://www.youtube.com/watch?v=llQt8-1YCJI

 

[audioguru2]

Load - car 60 watt lamp.

It draws 5A at 12V when hot and it draws maybe 50A when cold.
The moment that you connect it then it will try to draw 50A but the current-regulation will limit its current to only 3A by limiting or reducing the voltage.

If you turn the current-setting to maximum and the voltage to zero, connect the light bulb then slowly turn up the voltage it should work up to maybe 10V at 3A.

Your video shows that the warning LED lights when there is no load and the current-setting pot is turned down which is wrong. It is due to an input offset voltage of U3. Increase the value of R17 (it is now 33 ohms) to maybe 47 ohms or 68 ohms until the LED does not light when the current-setting pot is at minimum.

 

[mendimano1]

But what about if you want to charge a batterry with thats say for example 12 Volts and 2.5 amps....when battery  draws 5 amps...and you want to limit the current for a beater charging...when the gurrent limiter is activated...you cant regulate the voltage to 12 volts....
It draws 5A at 12V when hot and it draws maybe 50A when cold.
The moment that you connect it then it will try to draw 50A but the current-regulation will limit its current to only 3A by limiting or reducing the voltage.

If you turn the current-setting to maximum and the voltage to zero, connect the light bulb then slowly turn up the voltage it should work up to maybe 10V at 3A.

Your video shows that the warning LED lights when there is no load and the current-setting pot is turned down which is wrong. It is due to an input offset voltage of U3. Increase the value of R17 (it is now 33 ohms) to maybe 47 ohms or 68 ohms until the LED does not light when the current-setting pot is at minimum.

 

[audioguru2]

But what about if you want to charge a batterry with thats say for example 12 Volts and 2.5 amps....when battery   draws 5 amps...and you want to limit the current for a beater charging...when the gurrent limiter is activated...you cant regulate the voltage to 12 volts....

Set the voltage to 13.8V to 14.4V and set the current to 2.5A if you want. The current regulation will reduce the voltage to whatever the battery needs when it draws 2.5A. The voltage will slowly rise as the battery charges and the current will stay at 2.5a until the battery becomes near fully charged when the battery will reduce the current.

 

[mendimano1]

Let me inform you that i have changed the value of R17 from 33 Ohm to 47 Ohm, and now  the warning LED of an current limiter does not light when there is no load, thank you Audioguru.

Your video shows that the warning LED lights when there is no load and the current-setting pot is turned down which is wrong. It is due to an input offset voltage of U3. Increase the value of R17 (it is now 33 ohms) to maybe 47 ohms or 68 ohms until the LED does not light when the current-setting pot is at minimum.

 

[sparky666]

I measured the voltage of the project with a 10k resistor since that resistor was in hand, and the min voltage was 1.1V and the max was 30V, without it, it the min was 6.4V and the max 30V;with the output shorted,the min was 0.0V, but the max was 0.3V. And the two 2n3055 transistors that I use are connected with the right pins

 

[sparky666]

I forgot to mention that I connected a light bulb from a car which had approx.  1ohm resistance, and the project was working normally(min voltage 0.0V, max voltage 30.0V and max load 3A), so I'm totally out of guesses what is wrong...

 

[4017555]

Hello and Sorry for Bad English ..

i draw this circuit with Orcad 16.3 & multisim 11 But Output is 0v !! why ??

Please Help Me ...
I Need It ...

Thanks

 

[audioguru2]

i draw this circuit with Orcad 16.3 & multisim 11 But Output is 0v !! why ??

Many things will cause the output to always be 0V.
Post a PNG file of your schematic so I can see if something is wrong.
Maybe your SIM software does not know the details of the special opamps that are used in the fixed version.

 

[4017555]

Many things will cause the output to always be 0V.
Post a PNG file of your schematic so I can see if something is wrong.
Maybe your SIM software does not know the details of the special opamps that are used in the fixed version.

Thanks for answer .
I cant use Rv1 Pot because Orcad TL081 Not supported !
See this images :

 

[audioguru2]

I cant use Rv1 Pot because Orcad TL081 Not supported !

You have sketched part of tthe original schematic but transistor Q3 is missing. It drives an LED that warns when the current regulator is reducing the output voltage. The current regulator does not do anything when there is no load so it is not reducing the output voltage.

The original project has many errors and is not reliable because many parts are overloaded.
We have fixed it a few times for about 6 years.

You should use the latest version of the schematic that has been posted in this thread many times (see page #55 of this thread on Jan 27/2011).
You should also use modern SIM software that supports modern opamps.

 

[4017555]

Hi audioguru .

I Create this New circuit with Multisim 11 But Not Work !!

My Multisim Save file Attached . Please Help Me ...

0-30-Power_Supply-Multisim-11.rar

 

[audioguru2]

Hi audioguru .

I Create this New circuit with Multisim 11 But Not Work !!

My Multisim Save file Attached . Please Help Me ...

I don't have Multisim so I can't see your schematic.
Post your schematic as a screen save PNG file type.

 

[4017555]

Thanks PNG Attached

 

[audioguru2]

Thanks PNG Attached

Your Multisim schematic is a nightmare of crossed wires going all over the place. You changed all the parts designation numbers so it is too time-consuming to see if anything is wrong.

If you SIM it in Multisim then it probably will not work.
But if you build it from the corrected schematic then it will work perfectly.View attachment 41479

 

[maciek1234]

Hello.

I also tried to simulate circuit in multisim 11 and couldn't make it work.
Could someone have a look at the circuit if its ok?
All the components are numbered as in oryginal circuit (latest version)

Has any one managed to simulete circuit using any simulation software and got it worked correctly??
If yes could you tell what software you used and could you upload simulation file please.

Many thanks!

 

[maciek1234]

simulation jpg

View attachment 41480

View attachment 41481

 

[audioguru2]

simulation jpg

They have the transformer short-circuited to the output 0V which is wrong.

 

[maciek1234]

Thank you audioguru for your coments on the circuit.
Its only looks like the transformer is short-circuited with 0V
Below I attach beter picture of the ciuruit (its in 2 picutres actualy) and wolud be very greatfull for any coments,MAny thanks!

View attachment 41482

View attachment 41483

 

[audioguru2]

You don't know what you are doing and I also don't know what you are doing.

Your schematic shows a short-circuit and a capacitor value that is completely wrong.

View attachment 41484