An electrometer is a sensitive instrument used to measure electric charge or voltage. It can detect very small amounts of electric charge, making it useful in scientific research and various applications, such as in laboratories and industrial settings. Electrometers can help in understanding electrical properties and behaviors in materials. These devices often operate on the principle of electrostatic attraction or repulsion. Some electrometers use a capacitor to store charge, while others may employ a moving coil or a digital display to show measurements. They are essential tools in fields like physics, engineering, and environmental science.