18 Jan
2010
18 Jan
'10
4:26 p.m.
On 18 Jan 2010 at 18:26, Bill Sudbrink wrote:
I built a test load by putting three one Ohm 10W
resistors (available
at the local Radio Shack) in series. With the test load, the +9 rail
goes down to a little more than 8 and the +5 rail goes to about 4.8,
smooth as glass on my scope. With that test, I decided to go ahead
and reinstall the ICs. I've applied power and the +5 rail is between
5.1 and 5.2.
I strongly urge you to replace the 7805 and parallel resistor with an
LM323T unit. The pinout and package are the same, but the current
rating is 3A, not 1. This would give you a measure of protection
that the resistor + 7805 does not afford.
There are, of course, other regulator option, but the LM323T is the
simplest.
--Chuck