Looking at at adding a simple LED indicator in front of an solid state relay. Not sure if its more correct to put it in series or use two different resistors as shown in the example. The indicator LED while close in voltage is different. The SSR is 1.25v while the indicator LED is 2v. I think under driving the indicator LED low enough not to damage the SSR should still light it. I have also seen it implemented in a similar fashion. However is it really the most correct way?
The operating current range is between 3 and 50 mA, so a typical small LED current of 10-20 mA will drive both components. Either schematic will work. I would go with the upper one; if either diode fails, the external indicator will indicate it.