Junebug + external power source - Electronic Circuits Projects Diagrams Free

UTMonkey · 2nd May 2008, 08:23 PM

Hi All,

I am pretty certain this has been asked before but I cannot find the post.

The last few of my projects are breadboard based using the Junebug to program and debug, what would happen if I attach an external 5 volts to the breadboard power rails whilst having 5V supplied from the Junebug?

Would I need to detach the 5V line from the Junebug?

Regards

Mark

blueroomelectronics · 2nd May 2008, 08:27 PM

Nope, you might get some trickle current from your targets 5V supply but it won't hurt the Junebug. The 1N5817 diode on the Junebug is designed to block external DC(the +5V ICD pin) from powering the Junebug.

UTMonkey · 2nd May 2008, 08:49 PM

Great thanks.

UTMonkey · 3rd May 2008, 02:25 PM

Just thinking though, wouldnt 5V from the junebug and the 5V provided via the breadboard source equal 10V = (KVL)? or is it 5V parallel?

my electronics theory is very shaky....

binzer · 3rd May 2008, 02:52 PM

Quote:

Originally Posted by UTMonkey

Just thinking though, wouldnt 5V from the junebug and the 5V provided via the breadboard source equal 10V = (KVL)? or is it 5V parallel?
my electronics theory is very shaky....

It would be in parallel with the existing 5v source, like Bill said there is a blocking diode to eliminate back feeding to the Junebug.

Kryten · 3rd May 2008, 04:02 PM

And they have the same ground referance

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2nd May 2008, 08:23 PM	(permalink)
UTMonkey	Junebug + external power source Hi All, I am pretty certain this has been asked before but I cannot find the post. The last few of my projects are breadboard based using the Junebug to program and debug, what would happen if I attach an external 5 volts to the breadboard power rails whilst having 5V supplied from the Junebug? Would I need to detach the 5V line from the Junebug? Regards Mark

2nd May 2008, 08:27 PM	(permalink)
blueroomelectronics	Nope, you might get some trickle current from your targets 5V supply but it won't hurt the Junebug. The 1N5817 diode on the Junebug is designed to block external DC(the +5V ICD pin) from powering the Junebug. __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com

3rd May 2008, 02:25 PM	(permalink)
UTMonkey	Just thinking though, wouldnt 5V from the junebug and the 5V provided via the breadboard source equal 10V = (KVL)? or is it 5V parallel? my electronics theory is very shaky....

3rd May 2008, 04:02 PM	(permalink)
Kryten	And they have the same ground referance __________________ Simplicity rules Good enought - its perfect ?? 2 Gig of free online backup space Are you a Chemist?