I have a physical HP-15C in my desk and I use the HP-15C emulator on my phone. As you can probably tell, I used that calc in college engineering classes until m

I have a physical HP-15C in my desk and I use the HP-15C emulator on my phone. As you can probably tell, I used that calc in college engineering classes until mine got stolen. I replaced it with an HP-28S that I used for quite a while. I bought the physical 15C a few years ago - 30 years after my original was stolen.