Driving two different devices off a single pin

Other Hardware LEDs and Multiplexing
1

I want to drive two devices from the same pin. The two devices are an LED and an opto-couple....

The two devices are:

1 LED out of a 3 bar LED array - http://www.farnell.com/datasheets/100514.pdf
Opto-couple EL817 - http://www.sztuofeng.com/pdf/??EL817.pdf

But basically we have an LED 20mA 2V & EL817 50mA at 1.2V

At first I did have both devices in parallel then going on to 220ohm resistors and on to ground but the EL817 was not quite turning fully on.

2

Could you hook the pin to a pair of transistors?

3

Demonic69:
Could you hook the pin to a pair of transistors?

That was plan B :slight_smile:

I was hoping for an alternative if possible as with that plan it's quite a number of extra components as I'm driving the 3 LEDs and 3 opto-couples from 3 legs.

4

try them in series.

5

No good in series, in the end I had to use 3 X ( 3 resistors + 2 transistors) which meant that I had to switch to SMD parts and re lay the moveable components on the board so everything fit.