I want to drive a dual color led (common cathode) from an 10vpp ac source so that on positive excursions one color is lit and on negative portion the other color is lit.
The simplest way I have done this in the past is to put both leds (in opposite directions in parallel) in the feedback of an inverting opamp and then control the current to them via the resistor connected to inverting terminal.
In this situation I do not have the luxury of a spare opamp and space is limited.
There should be a simple way to do this with two transistors and some resistors but my simulations are not working out properly (using a 2n3904 and a 2n3906 I can get alternating flashing but it is not smooth or balanced)
any ideas?
The simplest way I have done this in the past is to put both leds (in opposite directions in parallel) in the feedback of an inverting opamp and then control the current to them via the resistor connected to inverting terminal.
In this situation I do not have the luxury of a spare opamp and space is limited.
There should be a simple way to do this with two transistors and some resistors but my simulations are not working out properly (using a 2n3904 and a 2n3906 I can get alternating flashing but it is not smooth or balanced)
any ideas?