Photogate

Introduction

A photogate sensor is a timing device used for very precise measurements of high-speed or short-duration events. Typical applications include free fall acceleration, the period of a pendulum, or the velocity of a ball rolling down a track. A photogate consists of a light source and a light detector. Whenever an object moves through and blocks the beam of light between the source and the detector, a signal is produced which can be detected by a Vernier interface to start and stop timing operations.

Design Objectives

• Build a photogate using an infrared phototransistor and LED
• Construct a simple voltage-divider circuit
• Use a Vernier Digital Breadboard Cable to make the necessary connections between the photogate circuit and the lab interface
• Use Logger Pro to time an event