The Mini-Beam-DC-Voltage Series offers self-contained opposed mode modulated Infrared Sensor pairs for 10 to 30 V dc operations. Standard sensor pairs have 3 m (10 ft) range and long range sensor pairs have 30m (100ft) sensing range. The sensor features Bipolar - one current sourcing (PNP) and one current sinking (NPN) open-collector transistor output configurations. Exclusive, patented Alignment Indicating Device system (AID™, US patent #4356393) lights a rear-panel mounted red LED indicator whenever the sensor sees a "light" condition, with a superimposed pulse rate proportional to the light signal strength (the stronger the signal, the faster the pulse rate).