How to choose the expanding flow diode?

Good morning~all

I am working on a project which is about electronics. My professional knowledge is limited cause I am just an enthusiast.

I would like to make a circuit of Dc voltage by using L7815. This is the L7815's datasheet . However,the current is so low just about 20mA,(here it need to output 2A). Then I surfaced the internet to find the solutions, and here it said I just need to add a transistor.But I don’t know how to build the outside circuit about expanding flow diode?

Does anyone here can help me?

Thanks a lot!

@li ming

I hope that https://www.heisener.com/ will help you solve your problems and find the answers you are looking for.

Hey! That's a classic situation when boosting current with those regulators! The "expanding flow diode" term is a bit confusing—what you actually need is an external pass transistor (usually a beefy NPN transistor like a 2N3055, for example).

The transistor takes on the heavy lifting of the 2A load current, and your L7815 just handles the precision control.

A quick search for "L7815 current boost circuit" will show you the simple schematic. It only needs the transistor and a couple of resistors to make it happen.