Hi can i ask you what is the easiest way to make from 5A 200mA in my power source?
The only cruit I found is this but i dont even know how to count it.

thx for your help

 

What is your objective? Adjustable current limit on your power source?

 

What is your objective? Adjustable current limit on your power source?

No, I want to have Imax 200mA.

 

hi k5,
Do you mean a variable 0V to 5Volt at 200mA Current power supply.?
E

 

Sounds like TS wants to limit a 5A PSU to 200mA output.

 

That is what R2 in your schematic is for - it is adjustable since it is a pot, but you could substitute a fixed voltage divider.

Exactly (and I use the term loosely) what kind of power source do you have?

 

I have transformer 2x 24V; 6,6A and i want to do 1x adjustable voltage from 0V to 30V with current protection to 5A. And as second I want to make not adjustable ±15V with Imax 200m. And I have no idea what is the easiest way to make that 200mA.

 

That is what R2 in your schematic is for - it is adjustable since it is a pot, but you could substitute a fixed voltage divider.

Exactly (and I use the term loosely) what kind of power source do you have?

So am I right about that if i set that P1 trim to good value it should work?

 

Change Rs2 to ~3.9 Ohms.

 

I have transformer 2x 24V; 6,6A and i want to do 1x adjustable voltage from 0V to 30V with current protection to 5A

For the bridge rectifier, capacitor output you have, you should derate the DC output current to no more than 3.5A to avoid overheating the transformer.

 

And as second I want to make not adjustable ±15V with Imax 200m.

Below is a simple, near bulletproof circuit, using the ubiquitous LM317, to generate the fixed 15V with a 200mA limit:

R3 determines the current limit (ILim = 1.25V / R3), and R1 determines the output voltage (Vout = 10.3mA * R1 + 1.25V).
The yellow trace shows the output load resistance change with time.

For the negative supply, just replace the LM317's with LM337's, and use a negative voltage input.

Edit: Note that the full-load power dissipated by U1 is over 3W and the short-circuit power dissipated by U2 is over 6W, so both need to be on appropriate heat-sinks.
If they are all mounted on the same heat-sink, then all but one need thermal isolation washers.

 

I use the one in the post above for some of my stuff, but with LEDs on the inputs and outputs so I can see when it is on and whether it is in current limit.

If @kuji5 as the circuit he posted in post #8 he can adjust R3 to get his desired current limit.
Edit: Changed R1 to R3

 

Here's the circuit with an added LED to show when it goes into current limit:
Of course the diodes' directions are reversed for the negative output.

 

Here's the circuit with an added LED to show when it goes into current limit:
Of course the diodes' directions are reversed for the negative output.

View attachment 282852

It works great thank you so much for your help <3

 

Here's the circuit with an added LED to show when it goes into current limit:
Of course the diodes' directions are reversed for the negative output.

View attachment 282852

Can I have a question? How does the LED signaling works and how did you determine the value of R4 = 3kOhms? Thank you for your answer.