1. Semiconductor gas sensor
2. MCU processing
3. Auto-check sensor failure
4. Auto reset after gas clears
5. Sound & flash alarm
6. 12V pulse output to drive solenoid valve to shut off gas supply
7. Relay output to drive exhaust fan to clear leaked gas
8. 24 hours aging tests of both PCBA and finished detectors to make it very stable
9. Double tests with gas when after two times of aging to make it very stable