🚀 go-pugleaf

> I have a question about the MC7805 5V 1A regulator. Can you parallel
> two of these devices together to derive a higher current?

Parallelling them is not very clean.  You have the problem that both
regulators will have *slightly* different output voltages.  The one
with the higher voltage will try to carry the full load, up to the
point where it goes into current limiting.  At this point the voltage
will drop till the second one picks up this excess load.  The effective
source impedance is quite high during this load pass-off.

You can always try to use a simple PNP buffer as such:
(Any high-current silicon PNP will do.)

~+8v in					    +5 out
  o---+----\	    /-------------------+----o
      |     \	   /			|
      |      v	  / 			|
      |    ---------	  +5v reg.      |
      |	       |	+--------+     	|
      |	2.7 ohm|	|        |      |
      +--\/\/\-+--------+ in  out+------+
      |        		|  gnd   |	|
      |         	+---+----+	|
     --- 0.1 uf //          |          --- 0.1 uf // 10uf tantalum
     --- 10 uf tant         V          ---
      | 		    	       	|
      | 				|
      v 				v

If you have problems with oscillations you can put a few 10's pf
capacitance between the base and collector of the PNP.  Invert this
circuit for a negative supply booster.

---
Wolfgang Rupprecht	ARPA:  wolfgang@mgm.mit.edu (IP 18.82.0.114)
TEL: (617) 267-4365	UUCP:  mit-eddie!mgm.mit.edu!wolfgang