Indicator LED error circuit- Help!

Thread Starter

ekremgusani

Joined Mar 20, 2011
157
G = green LED.
R = red LED.
D = 1N4148, or 1N914, or just about any diodes.
1K resistor will give about 10mA through the LEDs.

Bi-colour LEDs are available in 3 lead packages (don't get the 2 lead variety) in both common anode and common cathode configurations so the LED appears to change colour. Otherwise, 2 single LEDs can be used.
Try it on a breadboard. Hook up one green LED and resistor, then place the other red LED across the green one to make sure your LEDs work ok without the added series diode for the green one. It will not hurt to have the diode there anyway.
Can you just please explain how to do it if i want to reverse the led example. Red led to be the power indicator and the green led to be activated siren indicator? I tried just to reverse the led connections but it’s just the red led lite.
Thanks again.
 

MisterBill2

Joined Jan 23, 2018
8,405
Trying to understand the entire set of requirements is NOT "trying to act smart", but rather it is making an effort to fully understand the application so as to avoid giving poor advice.
 

dendad

Joined Feb 20, 2016
3,810
Can you just please explain how to do it if i want to reverse the led example. Red led to be the power indicator and the green led to be activated siren indicator? I tried just to reverse the led connections but it’s just the red led lite.
Add an extra diode in series with the red LED.
The idea is to make the forward voltage required of the LED you want to turn off higher than the one you want to be on.
 
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