What are the components used inside programmable logic controller?

Inside the chip itself? It's an IC, it is a component.





ICs are a monolythic structure with transistors, resistors, etc, but they are not components of the IC, they are part of it.





If you are talking about a controller box, it has several ICs, a power supply, bypass caps, connectors, and perhaps data input/output controls.





.What are the components used inside programmable logic controller?
Transisters.