I made myself a high-current regulator with a 7805 and 2n3055. I am now going to make a PCB. I attached the eagle CAD files. Anyone know if it will work? Are there any problems? (My first time using Eagle :))
If it is in the wrong place please report to moderator.
Thanks!
eagle.zip (16.5 KB)
It may work, but not very well.
Back in the days, a power transistor was added to increase the current capability of a common 78xx regulator.
But the (PNP) transistor was used across the regulator, not after the regulator as in your diagram.
Your circuit will have bad regulation.
Circuits like this are not used anymore because of heat loss.
Say you want to change 12volt into 5volt/5A.
The 2N3055 has to consume the difference between 12volt and 5volt, x 5Amp. That's 35watt.
Your 2N3055 has to be mounted on a heatsink for that.
A $5 switching regulator from ebay will do that with only 5watt heat loss.
Keep on making things with Eagle.
I learned a lot from using existing Eagle files, and improving the layout.
You could make some of the high current traces wider by right-clicking on one, click properties, width.
Or ripup one small track, choose layer and width on top, and re-route it. Use right mouse button for track shape.
Leo..
I actually found the circuit here. Using LM78XX Series Voltage Regulators Tutorial I do not have any PNP power transistors, but I have 2 TO-3 2N3055.
Back in the late '70s, in my first job, I was working on a product which had circuit like fig 13 on page 20 of the datasheet mentioned by TomGeorge.
Everything worked fine until you accidentally short circuited the output.
This would cause the PNP transistor to die.
Maybe the circuit of fig 14 would have cured that.
OK. I have dramatically redesigned the whole thing and I am using a LM2576 instead. The circuit is the recommended one here, http://www.ti.com/lit/ds/symlink/lm2576hv.pdf , except for the fact that COUT is 470uF. I will post the Eagle board and schematic as soon as I get to my other computer.
Here are the Eagle files.
eaglezip.zip (23.3 KB)
