Current regulator

Other Hardware General Electronics
1

Hello everyone,

Is there any built-in component that can regulate the output current to as low as 0.5 mA when the input is 6 V and 1 A?

Thanks

2

You may have to look for a low-dropout regulator, but the idea is still the same. 7805 voltage regulator can be connected as a current regulator.

What do you mean by 'built-in'? Do you mean built into the arduino?

3

Moved your post to here as you posted in a section whose description says do not post here.

4

No.

For a start 1A is only the maximum possible current a supply could supply. What is does supply depends on the load the voltage is driving.

But more than that it illustrates that you do not know how electricity works.

So tell us what you want to do this for and we will be able to offer practical advice on how to do what you want to do.

5

Hi, @MasoudHasany

What is the application?
Why do you need variable current output?

Thanks.. Tom.. :grinning: :+1: :coffee: :australia:

6

Hello,

Thanks all. Here is the application:
In my design, I have a supercapacitor that should be charged with a solar panel (6 V output). The charging current must not exceed 0.5 or 1 mAmp.

BR
Masoud

7

Hi, @MasoudHasany

Why do you need to limit the charge current?
How big is the PV, Watts?

Thanks.. Tom.. :grinning: :+1: :coffee: :australia:

9

Hi Tom,

Because it is related to the design of the supercapacitor. When the current is not limited, the IR drop is a lot. I want to limit that.

10

Hi, @MasoudHasany

What do you mean by "IR"?

Tom... :grinning: :+1: :coffee: :australia:

11

https://www.google.com/search?q=ir+drop&rlz=1C1KNTJ_enDK1036DK1036&oq=IR+drop&gs_lcrp=EgZjaHJvbWUqBwgAEAAYgAQyBwgAEAAYgAQyBwgBEAAYgAQyBwgCEAAYgAQyBwgDEAAYgAQyBwgEEAAYgAQyBwgFEAAYgAQyBwgGEAAYgAQyBwgHEAAYgAQyBwgIEAAYgAQyBwgJEAAYgATSAQgxOTY3ajBqMagCALACAA&sourceid=chrome&ie=UTF-8

12

Hi,
How big is your PV in watts?
What is its short circuit current?
Will you have a blocking diode to stop the capacitor discharging back into the PV when its output goes down in the dark?

What gauge wire are you using to connect the PV to capacitor and how long?

How much IR drop are you expecting/measured?

Thanks.. Tom.. :grinning: :+1: :coffee: :australia:

13

No.
Is there any reason you can't just use a resistor?

14

How is that possible when the voltage of the supercapacitor is changing during charging? Can you explain more?

15

So I guess using a resistor to limit the current is out. It easy and simple.
OK, just a suggestion

16

Google;

How a capacitor works

You will be surprised.
With no charge on a capacitor, there is no voltage on the capacitor.
As you charge the capacitor, the potential difference across the capacitor, the voltage, increases from zero.

Please answer;

Tom.. :grinning: :+1: :coffee: :australia:

17

Hi,

  1. It gives 120 mA as the max output. Considering that the voltage is 6 V, it is 720 mA.
  2. It depends on the light intensity. Am I wrong?
  3. Yes, I have.
  4. 28G.
  5. It totally depends on the charging rate. We want to keep it as low as possible. That is why I need to limit the current to not more than 0.5 mA.

BR
Masoud

18

What does that mean?
How do you get 720mA?

If the short circuit current is 120mA, then that is the maximum current you will get from the PV.

Have you calculated the volt drop across your 28g wire at 120mA?

Have you used Ohms Law?
What is the resistance of your length of 28g connecting wire?

I think you are OVER THINKING your project and need to do some more research.

PLEASE draw a simple schematic of your proposed circuit.

How big is the supercap?

Thanks.. Tom.. :grinning: :+1: :coffee: :australia:

19

If you don't want to use a resistor, you could use a current regulating diode.

20

Thanks. Something like this:
https://eu.mouser.com/ProductDetail/Semitec/S-501T?qs=wgO0AD0o1vsrGXznDcjjCw%3D%3D

21

Yes but you must realize that it will only provide a constant current while the voltage difference between the source voltage and the capacitor voltage is greater than 1.1V, below that, it basically acts as a resistor