UVTRON 是紫外線開/關探測器，可快速遠距離檢測火焰發出的微弱 UV，因而適合用于火焰探測器和火警。它們的光譜靈敏度范圍是 185 nm 到 300 nm，且對可見光完全不敏感。它們使設計具有簡單電路的高靈敏度、快速響應的 UV 檢測系統成為可能。
When UV light emitted from flames or discharges reaches the UVTRON and strikes the cathode, photoelectrons are released from the cathode surface. These photoelectrons are drawn toward the anode while colliding with gas molecules and ionize them, producing secondary electrons. The electrons then repeatedly collide with and ionize other gas molecules until finally reaching the anode. By using this phenomenon called gas multiplication, UVTRON amplifies the electrical current and outputs it as a signal.