A stud finder is a handheld device used to locate framing studs behind the final walling surface, usually drywall, in wood buildings. There are many different types of stud finders available, but most fall into two main categories: magnetic stud detectors and electric stud finders. Some devices employ radar technology.

Magnetic stud detectors work by detecting the walling fasteners or nails that are presumably attached to studs. They were the first type of stud finders and have been in use since the early 20th century. Electric stud finders, on the other hand, use changes in capacitance generated by density differences to determine where the stud is. They give an accurate view into the wall and show exactly where each stud is.

There are also instant stud finders that have multiple sensor plates and do not need to be moved across the wall to detect a stud. They use an algorithm to analyze the readings from the multiple sensor plates for a quicker, more accurate indication. Instant stud finders sense multiple regions of a wall simultaneously, including the center of a stud, edges of the stud, and regions without studs.

The newest stud finders in the industry implement radar technology. Using raw signals transmitted by their sensors, they are able to classify different wall types as well as the material behind the walls. This allows for detection of studs, pipes, wires, leaks, and even motion such as pests or rodents. One of their advantages is the ability to work on older houses, such as ones with lath and plaster wall types.

To use a stud finder, you need to turn it on and place it against the wall. The device will then scan the wall and indicate when it has found a stud. There are three different types of stud finders: low-end stud finders that use magnets or electricity to detect a stud, electronic stud finders that detect changes in the dielectric constant of the wall to find studs, and modern stud finders that use radar technology to find studs, pipes, and even wires.

In summary, a stud finder is a device used to locate framing studs behind the final walling surface in wood buildings. There are different types of stud finders available, including magnetic stud detectors, electric stud finders, instant stud finders, and radar stud finders. To use a stud finder, you need to turn it on and place it against the wall, and the device will indicate when it has found a stud.