Electronic test instrument with extended functions

摘要

An electronic test instrument in the form of a clamp meter has a non-contact voltage sensing circuit which includes a blade and sensor built into the clamp. The test instrument also has a shaker circuit that produces a tactile vibration in the presence of an AC voltage. The intensity of the vibration is proportional to the level of the AC voltage. A clean power indicator circuit is provided as well. The clean power circuit compares the level of harmonic distortion plus noise to the full signal and activates an LED if the distortion plus noise is within acceptable limits.