PRESS A BUTTON on this amazing new wristwatch and you see the time displayed directly in numbers. If you hold the button down, the seconds are counted off below the hour and minute numbers.

This electronic marvel, just introduced by the Hamilton Watch Co., has no hands and no moving parts, never needs winding and is accurate to within three seconds a month.

Called the Pulsar, it is, in fact, not a watch at all in the customary sense, but a wrist-size computer that tells time by counting the vibrations of a tiny quartz crystal. The crystal is excited by a rechargeable battery so it resonates at precisely 32,768 cycles per second. These vibrations are reduced to one pulse per second by an electronic counter. A computer module then determines the time to be displayed at any given instant according to the number of pulses it receives.

The numbers displayed on the watch face are actually formed by dozens of dot-sized light-emitting diodes that are turned on and off in changing patterns to produce the appropriate number digits.

The pushbutton switch is needed to conserve battery power until a visual indication is desired. The first Pulsars, due next year, will sell for $1500, but Hamilton hopes eventually to bring the price down through mass production.

SPECK-SIZED INTEGRATED CIRCUITS are so tiny they must be handled by tweezers under a microscope.