Atty State LED Indicator

[Krythis]

Here's a circuit I've been working on that would light a green LED during normal use and red if the atty lost connection or burnt out. Since it's been about 10 yrs since I took a circuits class I was hoping to get some feedback from those more experienced than myself before I start ordering parts

 

[bigblue30]

Krythis,

Nice curcuit. I do not see a "zero" ohm return path for the atty. The right side of the atty is B+ (postive battery) and the lowest path to ground I see is through the 100 ohm R2. 101.5 it too much resistance to fire the atty.

 

[Krythis]

I'm not sure about the resistors or their values. I built the circuit using a simulator and they were added during trial and error. If I remove the 100ohm resistor the LEDs wont activate, other than that I don't see a purpose for it.

 

[asdaq]

Ktythis, just an idea not meaning to distract-- why not use a red-green LED that has 3 legs instead of 2 seperate, like in our chargers? They are available in various color pairs too.

 

[Krythis]

Ktythis, just an idea not meaning to distract-- why not use a red-green LED that has 3 legs instead of 2 seperate, like in our chargers? They are available in various color pairs too.

This is just a 'rough sketch' right now, I would like to condense the circuit as much as possible based on the feedback I receive. I plan to use one LED, but I didn't see them available in the simulator I use

 

[Krythis]

Any ideas as to why the LEDs wont work without that 100ohm resistor?

 

[KYFlyer67]

Any ideas as to why the LEDs wont work without that 100ohm resistor?

LED's work on very low voltage. Without a resistor, you'll fry the LED quickly.

 

[ADZ_420]

Move the resistor above the green led in your circut and go strait to ground on the atty, should work, ill test this for ya when i get back home that is multisim ur using right? if wrong let me know what sim ur using and ill check it out for ya


EDIT: try a 220 instead of 100 to further limit current outside of the atty

 

[Krythis]

Move the resistor above the green led in your circut and go strait to ground on the atty, should work, ill test this for ya when i get back home that is multisim ur using right? if wrong let me know what sim ur using and ill check it out for ya


EDIT: try a 220 instead of 100 to further limit current outside of the atty

Yup, Multisim 11.0.

When I remove the 185 above the green LED and changed the 100 to 220 I'm unable to turn the LED indicators off using switch J2.