Works with leakage current from 2-wire proximity switches.

Application e.g. limit switches and long cables.

Main benefits comparing to electromechanical relays and opto coupled relays:

- No limited lifetime, 7 to 10 year warranty time depending on relay type
- Relatively high tolerance against noises
- Guaranteed switching on and off -levels
- 100 % clear status indication
- Relatively high transient protection
- Extreme reliability
- No minimum load requirement