Switching higher voltage current source

It's just something I realized I don't know how to do and I should know how to do.

If only other newbies had your ambition and high goals...

FYI,

"Knowing how to do things works better when you know how to do things..."

(meaning all your designs will work the first time if you follow the right steps in the process:
ie: 1-start with design criteria
2- make schematic and parts list
3- prototype circuit highlighting each connection on the schematic as you make it and doing a continuity check of each connection.
4- Measure power supply voltages BEFORE connecting them to the power bus on the breadboard.
5 - Measure all important circuit voltages after power up.
etc
etc
etc