Description
The sensor has a sapphire window that is transparent to UV light and can withstand the compressor discharge temperature and pressure. It has a lens inside that focuses the light on a silicon carbide photodiode in a hermetic package. The photodiode is wired to a MOSFET input amplifier. The amplifier has a high initial gain, which automatically shifts to a lower gain in order to accommodate a wide range of input light level without saturating. The sensor regulates the supply current in proportion to the amount of UV light present. Both power and signal are transmitted on the same two wires. The sensor can be powered from a dc voltage between 12 and 30 volts. The whole transducer is sealed and filled with dry argon.