The MicroLab Drop Counter is a reflective infra-red sensor that counts drops leaving a burette. Since drop size is determined by solution viscosity and the shape of the burette tip and not by pressure head, drop size will remain constant as solution level drops in a burette. This sensor provides an easy way to automate titrations.
The size of a drop from a burette can be calibrated by counting drops into a graduated cylinder.

The sensor contains both a high-power infra-red emitting diode and a photo-transistor. A background correction circuit permits cancellation of ambient sunlight, which has a strong infra-red component.

A green LED indicates that power is applied to the sensor, and a red LED blinks as a drop is counted. Maximum count rate is 40 drops per second. The drop counter can be mounted on a ring stand with the four-inch long, 1/2 inch diameter aluminum rod. The drop counter connects to the MicroLab 402 and 500-series instruments with a full-sized phone plug.

See also the MicroLab Drop Dispenser (Model 2260)