# RGB Common anode LED parallel circuit not glowing yellow

Hi

For my project I have 10 leds connected in series and I am trying to make them all glow yellow, so I need half the current to go through the green led and the other half to go through the red led. As it is common anode, the anode is connected to a 9V battery through a 220 ohm resistor. The two legs ( red and green) are then attatched together at the end of the circuit, this wire then goes into the negative of the 9V battery. However the leds glow red when both the red and green wire go into the negative and they glow green when only the green wire goes into the negative. I am guessing that this may be as the red led in the RGB led has the least resistance.

The circuit

Battery + ---- resistor ----- +leg of led ------ + leg of led ----- + leg of led ----R leg of led ------R leg of led ------R leg of led Battery - __________/_G led of led -------G leg of led -----G led of led

The slash represents where the R wire and the G wire are joined.

Thanks :)

bexx123:
I am guessing that this may be as the red led in the RGB led has the least resistance.

Not quite but similar. The red LED has a lower forward voltage so the voltage drop across both LEDs is just that. This is too small for the green LED to begin conducting.
You need two resistors, one on each cathode leading to the battery minus.

Just to be clear take the resistor out of the anode and put a resistor in each of the cathodes. The resistors might have to be different values to balance the colour but start with them as the same values.

Thanks for the replies guys, as well as informing me of the theory behind it :) Problem solved!