Abstract: A solid state motor speed control is described that is capable of controlling a motor so that it operates quietly, eliminating annoying buzzing noises that would otherwise be generated by the motor's windings. The invention provides for motor speed control with infinitely variable speed control settings. Rather than use triacs that generate RFI noise and cause motor windings to buzz due to their inherent avalanche switching, the invention utilizes power FETs or IGBTs to provide the switching function to control power delivery to the motor load . The power switches are controlled by an oscillator that generates a pulse train with a duty cycle controllable by the user. A filter shapes this signal into a trapezoidal control signal that drives the gate input of the power FET or IGBT switch. A kick start circuit turns the motor on initially for two to three seconds to overcome the inertia of the motor and its load.

Abstract: A solid state motor speed control is described that is capable of controlling a motor so that it operates quietly, eliminating annoying buzzing noises that would otherwise be generated by the motor's windings. The invention provides for motor speed control with infinitely variable speed control settings. Rather than use triacs that generate RFI noise and cause motor windings to buzz due to their inherent avalanche switching, the invention utilizes power FETs or IGBTs to provide the switching function to control power delivery to the motor load. The power switches are controlled by an oscillator that generates a pulse train with a duty cycle controllable by the user. A filter shapes this signal into a trapezoidal control signal that drives the gate input of the power FET or IGBT switch. A kick start circuit turns the motor on initially for two to three seconds to overcome the inertia of the motor and its load.

Abstract: A key touch dimmer includes a switching device through which AC line current is passed to brighten a lamp in response to a control signal generated by a microprocessor. The microprocessor receives an input indicative of the zero crossing points of the AC line current and synchronizes this input with its own internal clock circuitry to generate a firing signal for the switching device at the correct phase angle in the next half cycle of the AC line current. The dimmer has memory capability whereby the lamp, when turned back on, will brighten to a preset level. This brightening is accomplished in a gradual manner. Likewise, a turned off lamp will fade to zero brightness, with the dimmer retaining the preset brightness level. The microprocessor shuts down quickly in the event of a power outage to preserve memory. An optional display includes a plurality of LEDs for indicating light level. Other options include providing the dimmer with several keys, each of which can be adjusted to a respective preset level.

Abstract: A key touch dimmer includes a switching device through which AC line current is passed to brighten a lamp in response to a control signal generated by a microprocessor. The microprocessor receives an input indicative of the zero crossing points of the AC line current and synchronizes this input with its own internal clock circuitry to generate a firing signal for the switching device at the correct phase angle in the next half cycle of the AC line current. The dimmer has memory capability whereby the lamp, when turned back on, will brighten to a preset level. This brightening is accomplished in a gradual manner. Likewise, a turned off lamp will fade to zero brightness, with the dimmer retaining the preset brightness level. The microprocessor shuts down quickly in the event of a power outage to preserve memory. An optional display includes a plurality of LEDs for indicating light level. Other options include providing the dimmer with several keys, each of which can be adjusted to a respective preset level.

Abstract: A key touch dimmer includes a switching device through which AC line current is passed to brighten a lamp in response to a control signal generated by a microprocessor. The microprocessor receives an input indicative of the zero crossing points of the AC line current and synchronizes this input with its own internal clock circuitry to generate a firing signal for the switching device at the correct phase angle in the next half cycle of the AC line current. The dimmer has memory capability whereby the lamp, when turned back on, will brighten to a preset level. This brightening is accomplished in a gradual manner. Likewise, a turned off lamp will fade to zero brightness, with the dimmer retaining the preset brightness level. The microprocessor shuts down quickly in the event of a power outage to preserve memory. An optional display includes a plurality of LEDs for indicating light level. Other options include providing the dimmer with several keys, each of which can be adjusted to a respective preset level.