@andrewmm I would like to know how to use the normalized figure 4 and 6 to read out what Vce can be expected when If=8mA and Ic=140mA. The specified CTRmin of 500% is when If=1mA and Vce=5V.

 

It has been explained to you a number of times, due to component parameter spread, you cannot use those two plots to give you a specific value for Vce at the values you are posting.
Suffice to say at 150mA, Vce will be most likely 1.1V as stated in the datasheet.
At 140mA I would accept a Vce of 1.1V.

Could you say why it is important that you need to need the exact value of Vce.??

 

@andrewmm I would like to know how to use the normalized figure 4 and 6 to read out what Vce can be expected when If=8mA and Ic=140mA. The specified CTRmin of 500% is when If=1mA and Vce=5V.

So take step back,

The CTR specifies the current that can flow in the output given a given current on input. normal transistor theory.

So given CTR off 500%, then put 8mA in, you can put up to 40 mA through the output transistor. ( 8 * 5 )

To put 140 mA through , you would need to put 28 ma into the opto, if it can take that.


So do you want to put 140 mA through the output transistor, or 40 mA.

 

140mA.

I think fig 4 means additonal x5, as the 500% is specified for If=1mA, Vce=5V.

If so then
ic= If * 500% * 5 = 8*5*5 = 200mA.

But I think ic must be derated to hold up for a lower Vce than 5V, using figure 6.