Digital electronic alarm watch

An electronic digital alarm wristwatch in which a piezoelectric crystal is energized with an alternating current signal to generate an audible alarm tone, comprising:

• a digital electronic circuit for producing a first alternating current signal varying between ground potential and a second potential at an audio frequency, said digital electronic circuit comprising:
• a crystal oscillator utilized as the fundamental time base for said wristwatch;
• and
• means for dividing said fundamental time base signal by a factor sufficient to produce said first alternating current signal;
• and
• noninductive solid state circuit means responsive to said first alternating current signal for alternately applying a positive and negative voltage across said piezoelectric crystal to drive said crystal in a bidirectional manner.

An electronic digital alarm which including a piezoelectric crystal having a pair of electrodes for producing an audible tone, comprising:

• a watchcase;
• circuit means mounted within said watchcase for driving said piezoelectric crystal, said circuit means comprising a noninductive solid state bidirectional driver circuit comprising:
• the fundamental time base oscillator for said electronic wristwatch;
• and
• means for dividing said fundamental time base frequency to produce an alternating current signal at an audio frequency;
• means for mounting said crystal to said watchcase, said means electrically isolating said crystal from said watchcase;
• and
• means for connecting said pair of crystal electrodes to said circuit means independent of said watchcase.

An electronic digital alarm wristwatch having a piezoelectric crystal alarm element including a pair of surface electrodes for producing an audible alarm tone, comprising:

• means for producing an alternatively current signal at an audio frequency, said means comprising:
• the fundamental time base oscillator for said electronic wristwatch;
• and
• means for dividing said fundamental time base frequency to produce said alternating current signal at an audio frequency;
• means for applying said alternating current signal to one of said surface electrodes of said piezoelectric crystal;
• and
• an inverter connected between said alternating current signal and the other of said surface electrodes of said piezoelectric crystal.