I have a question to help me understand better.
I am using the following circuit on a breadboard:
I want to connect a second led, LED2, from the comparator output (2) to ground,
that would light when LED1 doesn't. It doesn't work. Here is what I tried:
Since LED1 is connected to +V, it works when the comparator outputs -V, right? So that is 10V in this case
If LED1 has a voltage drop of 2V then the 330ohm resistor has a voltage drop of 8V. If LED1 draws 20mA then the resistor is 8V/20mA which is 400 ohms, which is about 330 so I think this is correct.
I tried calculating the second resistor (not in picture) in the same way. The output voltage now has to be +V, the voltage drop is now 5V. The resistor would be 3V/20mA which is 150ohms.
I measured LED2 with a multimeter and I have a voltage that is higher than 2 V, but LED2
does not light,
I tried for all values of the potentiometer, it doesn't. I checked the LED, it works well, just not in this case. I could use a transistor as an inverter but why doesn't this work? Thank you.
I am using the following circuit on a breadboard:
I want to connect a second led, LED2, from the comparator output (2) to ground,
that would light when LED1 doesn't. It doesn't work. Here is what I tried:
Since LED1 is connected to +V, it works when the comparator outputs -V, right? So that is 10V in this case
If LED1 has a voltage drop of 2V then the 330ohm resistor has a voltage drop of 8V. If LED1 draws 20mA then the resistor is 8V/20mA which is 400 ohms, which is about 330 so I think this is correct.
I tried calculating the second resistor (not in picture) in the same way. The output voltage now has to be +V, the voltage drop is now 5V. The resistor would be 3V/20mA which is 150ohms.
I measured LED2 with a multimeter and I have a voltage that is higher than 2 V, but LED2
does not light,
I tried for all values of the potentiometer, it doesn't. I checked the LED, it works well, just not in this case. I could use a transistor as an inverter but why doesn't this work? Thank you.