Looking at the below schematic, with LED1 being a red LED (1.7V forward voltage) and LED2 being a green LED (3.2V forward voltage), I have a few questions that probably reflect lack of some fundamental principles of circuits, and I hope someone can get me into the clear :) [EDIT: When I say "Q1 is ON", I mean that I am supplying a 5V "high" signal to input IN1]
- if Q1 is ON, LED1 will shine and LED2 will be off. What are the voltages at V1 and V2? [My assumption is that they are both 1.7V as there is just one resistor (R2) in the path]
- if Q1 is OFF, LED1 will be off and LED2 is ON. The voltage at V2 is now 3.2V (the forward voltage of LED2). Correct?
Now imagine a scenario where LED1 is green and LED2 is red.
- if Q1 is ON, both LED1 and LED2 will shine (though LED1 only shines very faintly). Why is this? What is the voltage at V1 and V2? [From the observation that both LEDs are on I think V1=V2=3.2V, but I fail to see why since my first observation in question 1. above seems to say that V1=V2=1.7V - so I would have expected 1.7V here too and hence LED1 would not be lit].
- if Q1 is OFF, LED1 will be off and LED2 is ON. Voltage at V2 is now 1.7V (the foward voltage of LED2). Is this also correct?