[DonRotolo]

OK, so no CPU. Actually makes it harder.

Super-simple: A motor that runs at 1 RPD (Rev Per Day). Or at least a system that spins the whole assembly one revolution per day. Runs continuously. Once in a while you should re-set it to point at the sun, because nothing is perfect... (The issue is how to manage wiring to the fixed earth.)

Simple: Use a relay to run a very slow motor. Make an "eye" (see below) to detect the sun's position. Use an Op-Amp to detect when the sun has passed the "eye" and move the motor a little until it points at the sun again. Feedback loop!

Eye: Just a sensor at the bottom of a tube. More than one sensor, actually: One when aimed "right at" the sun, one when aimed "sun has moved". Maybe the 'right at' sensor is 'a little further' so the system moves less often. Like once every 30 minutes. Oh, and a timer of some type to reset to start after, say, 6 hours of darkness. Simple but effective.

More complex: Several sun sensors for an Eye, logic for movement even if there's no sun, reset timers, and so on. But now we would be better off with software control...

Jaguar? Way overkill, adds way too much complexity. If you don't want to use a relay and a very slow motor, then get an H-Bridge chip and use a variable duty cycle to control motor speed. Jaguars need too much love and affection to work well from a simple circuit.