The MIR-65 Series incorporate proven sensing technologies, together with advances in materials and electronics technology. Having a wide operating voltage of 9-33VDC, the MIR-65 Series detectors can be integrated into most Fire/Security systems. The MIR-65 Series wide voltage range family consists of photoelectric smoke, ionization smoke, and heat detectors. The sensing part of the ionization detector consists of two chambers - an open outer chamber with a second semi-sealed reference chamber within. Mounted in the reference chamber is a low activity radioactive foil of Americium 241 which enables current to flow between the inner and outer chambers when the detector is powered up. As smoke enters the detector, it causes a reduction of the current flow in the outer chamber and, hence, an increase in voltage measured at the junction between the two chambers. The voltage increase is monitored by the electronic circuitry which triggers the detector into alarm state at a preset threshold. A highly visible external red LED flashes when the detector is in operational standby and changes to steady in alarm state.