I have 3 Red LEDs and a 3 volt cr2032 coin cell. All the LEDs are in series with the cell. Obviously, none works as the combined forward voltage is more than supply voltage. But voltage across each LED is 0.12 volt, but it should be around 1 volt. The main problem is with sum of the voltages; the supply voltage is showing 2.88 volts on multimeter whereas adding the voltage across each led gives me only 0.36 volts. Where is the rest of the voltage? since Total voltage = V1 + V2 +V3. Is there any theory behind it? The same problem occurs with LEDs of different forward voltages with the same cell. For example, white in series with red.
I think that when these LEDs are in series there is a small current flowing through the circuit. And according to its V-I curve, for that small current, LED gets a particular voltage across it. Because when only 2 LEDs of same forward voltage (same colour) are in series they satisfy V=V1 +V2. Please help with this one and thanks already.