A CPU is made-up of an ALU (arithmetic logic unit), FPU (floating point unit), control unit (controlling interaction between CPU and other devices along the bus or buses), memory controller, and et cetera. All that stuff inside a CPU basically comprises of registers, logic gates, multiplexors, and timers on a microscopic level.

What I want to know is: what travels through a CPU to make a calculation? Is it a photon particle? Is it an electron particle? What particle is it that triggers all those logic gates and multiplexors and timers?

Also, what is held inside a register? If the CPU stored a value inside a register, what is physically in there??


I've never known the answer to these questions. Thanks, in advance, for your responses.