Electromagnetic drive circuit

An electromagnetic circuit comprising:

• a coil for detecting and driving a permanent magnet;
• a reference voltage source for generating a reference voltage;
• a comparator responsive to voltage induced in said coil by the magnet and to said reference voltage to generate an output signal when induced voltage of said coil exceeds said reference voltage;
• means for generating a drive pulse for driving said coil in response to said output signal from said comparator;
• and
• means for adjusting the duration of said drive pulse in accordance with the amplitude to said induced voltage to ensure that said drive pulse occurs when the amplitude of said induced voltage is at a maximum.

A method for correcting the motion of a pendulum, comprising the steps of:

• inducing voltage in an electromagnetic coil representative of the motion of the pendulum;
• comparing said induced voltage with a predetermined reference voltage and generating an output signal when said induced voltage exceeds said reference voltage;
• generating a drive pulse for said coil of predetermined duration in response to said output signal;
• and
• changing said reference voltage upon expiration of said drive pulse in response to the presence or absence of said output signal.

A method for correcting the motion of a pendulum, comprising the steps of:

• inducing voltage in an electromagnetic coil representative of the motion of the pendulum;
• comparing said induced voltage with a predetermined reference voltage and generating an output signal when said induced voltage exceeds said reference voltage;
• generating a drive pulse for driving said coil in response to said output signal, and
• adjusting the duration of said drive pulse in accordance with the rate of change of said induced voltage to ensure that said drive pulse occurs when the amplitude of said induced voltage is at a maximum.