The Texas Electronics, Inc. TR-525S Siphoning Rainfall Sensor is a remote tipping bucket style rain gauge that measures the amount of liquid precipitation. It utilizes a unique siphoning mechanism that allows for a wide range of accuracy. Incorporating this siphoning system allows the rain gauge to control the "flow rate" of accumulated precipitation. This metering geometry assures higher levels in both accuracy and repeatability during periods of extremely heavy rainfall.

The TR-525S rain gauge is a freestanding receptacle for measuring precipitation. It contains an open top, which allows rainfall to fall into the upper portion, which is called the collector. The 4" deep collector is specially designed to prevent splash out and overflow, two possible causes for loss of accuracy during extremely heavy rainfall events. Collected water is siphoned by a regulated flow into a mechanical device (tipping bucket). The tipping bucket then incrementally measures the rainfall accumulation and causes a momentary closure of a switch. As water is collected, the tipping bucket fills to the point where it tips over. This action empties the bucket in preparation for additional measurement. Water discharged by the tipping bucket passes out of the rain gauge with no need for emptying.