It is depended to aircraft type.
No all aircraft have typical Carb Heat system like C1x2 as we see 
In other sircrafts it can be in engine de-ice protection system, cowl flaps control, …
It is depended to aircraft type.
No all aircraft have typical Carb Heat system like C1x2 as we see In other sircrafts it can be in engine de-ice protection system, cowl flaps control, …