A pulse induction metal detector having high efficiency and sensitivity.
Within the scope of the invention is a high efficiency hand-held metal
detector for detecting a metal object, comprising a coil and a source of
current flow in the coil. The source is adapted to produce one or more
pulses of current in the coil. Preferably, at least two of the pulses are
spaced apart in time at least about 20 microseconds during which current
flow in the coil is substantially constant. The metal detector also
comprises a detecting circuit for detecting a response to the current
pulses, and a sampling circuit for sampling the response at predetermined
times at least during the time of one of the pulses.