Technically, every relay or transistor could be replaced by an ideal switch if there was such a thing.
However, I learned that those parts are satisfactory in most cases. Thus, I'm looking for a scenario where either:
- a certain device can't be built because it would require such an ideal switch
- the ideal switch would improve the performance (cost, efficiency, ...) of a device to such a degree that the alternative (relay/ transistor/ other switch) is no longer a meaningful option (assuming that the ideal switch costs the same as a relay/ transistor suitable for the same application)
Ideally, I'm looking for power-switching applications since I learned that RF-MEMS come close to the idea of an ideal switch. Thus HF/ RF applications are less suitable because the next best alternative (RF-MEMS) is already good.
I have already researched the following solution that could serve as an inspiration:
Electrical motor controllers use three-phase AC. They could technically be switched on by a TRIAC. However, the heat emission would be too much for most casings. On the other hand, a relay can't handle the current peaks that occur when the motor starts. Thus, they use the TRIAC to switch on the motor (to handle the current peak) and then short-circuit the TRIAC with a relay to avoid heat emissions. An ideal switch could replace the hybrid construction with one switch. (This should serve as an example - saving one component is too little impact to qualify as a solution, unfortunately. It has only a minor impact on the overall cost of the device).
Edit: An ideal switch has the following properties:
- if open, it is an open loop (infinite resistance)
- if closed, it has zero resistance (short-circuit)
- switching speed is (close to) infinite
- does not require energy to be operated (or very, very little)
It's size would be 10% of the next best alternative.