AC Screw Driver Testers
Mains Testers
Here are two types of testers purchased in the local electrical stores. The top one (Box only) has a small battery and a LED indicator. It is at full brightness, several inches away from any TV screen, and bright several feet from fan motors. It is sensitive to two cores mains cable, at several inches. With electrical appliances it's very sensitive if they are not completely grounded, and will detect a circuit loop if placed against the sole of a rubber shoe. Jumping up and down also produces a bright flash. The trade name shown on the box is "MetStar"
The lower item shown, is a similar device at detecting very small electrical signals and has a built in buzzer with a two position sensitivity switch. It also runs off two small batteries. This is the most sensitive detector of the two and has been in my tool box for many years.