Abstract: A driver circuit that is responsive to an input AC voltage provides a variable drive signal to a load circuit, such as, a solenoid coil, for each actuation of a switch where the variable drive signal duration is determined by the setting of a variable resistor. In one embodiment, a sine wave shaper produces a positive edge variably delayed square wave timing signal for a continuously clocked flip-flop. In response to the switch actuation, the clocked flip-flop generates a control signal for a selected period of time that is related to one cycle of the AC input voltage. In another embodiment, a one shot produces a positive edge variable delayed square wave timing signal in response to the switch, the signal then being received by another one shot which creates a control signal for a selected period of time that is related to one cycle of the AC input voltage. The selected period of time occurs only during the positive portion of the input AC voltage cycle.

Abstract: A driver circuit that is responsive to an input AC voltage provides a variable drive signal to a load circuit, such as, a solenoid coil, for each actuation of a switch. A sine wave shaper produces a positive edge variably delayed square wave timing signal for a continuously clocked flip-flop. In response to the switch actuation, the clocked flip-flop generates a control signal for a selected period of time that is related to one cycle of the AC input voltage. The selected period of time occurs only during the positive portion of the input AC voltage cycle. The control signal is employed to generate the drive signal for the load circuit. The driver circuit provides switch bounce rejection equal to one cycle of the AC input voltage.

Abstract: A pair of similar oscillators are coupled to each other such that when their natural resonant frequencies are close together they lock in and operate as synchronized oscillators over a predetermined range which can be selected by control of circuit parameters. Within the range where the oscillators are locked to be equal in frequency the phase angle between the frequency generated in each oscillator can be used as a measure of the influence on the resonant frequency of one oscillator relative to the other and where this influence is due to the parameters of an external test piece or the like influencing one oscillator, the measurement of phase angle is a measurement of a characteristic or parameter of the test piece.

Abstract: A detection and control apparatus for a textile machine having a coil through the field of which the machine needles pass individually and a pair of coupled oscillators operating in frequency step with the phase change due to a broken or damaged needle passing through the field of the coil detected as the modulation on the oscillation to control stopping the machine.