build a simple 5v power supply for digital circuit

"Spehro Pefhany" "Phil Allison"

Remaining within context is a real trial for you.

......... Phil

And the circuit description is demented, the output topology is not a 'voltage divider', he's putting some ridiculous amount of current through that LED, the whole thing is bad. No wonder that generation of kids just threw their hands up and quit electronics.

The pos is intractable as shown. Note that S2 is more likely a break-before-make, opening the 7805 return for even a few hundred usecs is not a good idea, output heads for the upper limits, then filtering the output with a reasonable value of capacitance is also problematic with that dammed switch too.

My context (in this thread)is hobby-level power supply circuits. Switching zeners rather than resistors is not an unreasonable approach, but we're still left with the spiking-during-switching issue.

Right, okay, bad memory, more like a 2:1 difference.

Best regards, Spehro Pefhany

Yes, it was mentioned, you're just a little late :)

Everyone seems to agree the schematic is a POS, any links to what more than one person believes to be a decent 5V PS?

You know, that's a good catch. Power supplies to many of us are like car's. We assume to much..

You get in your car to drive it, you shouldn't have to question if you have an engine in it! You just naturally assume that. But then again, that analogy maybe flawed if you live in a shady neighborhood :)

In my opinion, you would be better off with fixed post regulators of every voltage you need all branching off from the same bridge and filter cap..

If you want a variable out, you can create one from one of the higher voltage fixed post regulators with 2 Resistors and a pot.

Some Links.

"Phil Allison"

...... Phil