Abstract: An air handling unit has an interior shell, an exterior skin associated with the interior shell to form a wall space at least partially bound by each of the interior shell and the exterior skin, and a control component at least partially carried within the wall space. A cabinet for an air handling unit has at least one wall comprising an interior shell and an exterior skin associated with the interior shell to form a wall space at least partially bound by each of the interior shell and the exterior skin. The at least one wall at least partially defines a fluid duct of the cabinet and a control component is at least partially disposed within the wall space.

Abstract: An air handling unit has an interior shell, an exterior skin associated with the interior shell to form a wall space at least partially bound by each of the interior shell and the exterior skin, and a control component at least partially carried within the wall space. A cabinet for an air handling unit has at least one wall comprising an interior shell and an exterior skin associated with the interior shell to form a wall space at least partially bound by each of the interior shell and the exterior skin. The at least one wall at least partially defines a fluid duct of the cabinet and a control component is at least partially disposed within the wall space.

Abstract: An HVAC switching circuit may comprise a current source circuit charging a capacitor used to power an HVAC DC power relay coil. The power relay coil terminal is connected to an activation control circuit which comprises at least one of (1) each of (a) a threshold circuit which activates a first transistor to energize the power relay coil when the voltage across the threshold circuit reaches a first threshold value and (b) a regenerative feedback circuit configured to lower the first threshold value to a second threshold voltage, and (2) a voltage divider connected between a first terminal on the power relay coil and the negative DC supply, and a programmable shunt regulator, configured as a level triggered switch, programmed by the voltage divider and connected between the second power relay coil terminal and the negative DC supply.

Abstract: An HVAC switching circuit may comprise a current source circuit charging a capacitor used to power an HVAC DC power relay coil. The power relay coil terminal is connected to an activation control circuit which comprises at least one of (1) each of (a) a threshold circuit which activates a first transistor to energize the power relay coil when the voltage across the threshold circuit reaches a first threshold value and (b) a regenerative feedback circuit configured to lower the first threshold value to a second threshold voltage, and (2) a voltage divider connected between a first terminal on the power relay coil and the negative DC supply, and a programmable shunt regulator, configured as a level triggered switch, programmed by the voltage divider and connected between the second power relay coil terminal and the negative DC supply.

Abstract: An HVAC switching circuit may comprise a current source circuit charging a capacitor used to power an HVAC DC power relay coil. The power relay coil terminal is connected to an activation control circuit which comprises at least one of (1) each of (a) a threshold circuit which activates a first transistor to energize the power relay coil when the voltage across the threshold circuit reaches a first threshold value and (b) a regenerative feedback circuit configured to lower the first threshold value to a second threshold voltage, and (2) a voltage divider connected between a first terminal on the power relay coil and the negative DC supply, and a programmable shunt regulator, configured as a level triggered switch, programmed by the voltage divider and connected between the second power relay coil terminal and the negative DC supply.

Abstract: An HVAC switching circuit may comprise a current source circuit charging a capacitor used to power an HVAC DC power relay coil. The power relay coil terminal is connected to an activation control circuit which comprises at least one of (1) each of (a) a threshold circuit which activates a first transistor to energize the power relay coil when the voltage across the threshold circuit reaches a first threshold value and (b) a regenerative feedback circuit configured to lower the first threshold value to a second threshold voltage, and (2) a voltage divider connected between a first terminal on the power relay coil and the negative DC supply, and a programmable shunt regulator, configured as a level triggered switch, programmed by the voltage divider and connected between the second power relay coil terminal and the negative DC supply.

Abstract: An air handling unit has an interior shell, an exterior skin associated with the interior shell to form a wall space at least partially bound by each of the interior shell and the exterior skin, and a control component at least partially carried within the wall space. A cabinet for an air handling unit has at least one wall comprising an interior shell and an exterior skin associated with the interior shell to form a wall space at least partially bound by each of the interior shell and the exterior skin. The at least one wall at least partially defines a fluid duct of the cabinet and a control component is at least partially disposed within the wall space.

Abstract: An automatic lighting controller applies a turn-off control signal to a gate controlled power switch for switching OFF lighting when a timer circuit determines that motion activity above a threshold level has not occurred within the controlled area during a prescribed interval. A counter produces a grace period count signal and a reset count signal, with the grace period count signal occurring within a predetermined sub-interval, for example, one count cycle prior to the reset count signal. The grace period count cycle (N-1) interval is adjustable, for example, from about 0.6 second (for test purposes) to about 14 seconds. The grace period count signal enables an audio transducer which provides an audible alert that the lights are about to be switched OFF automatically. A person in the controlled area can override the impending automatic shutoff simply by initiating some motion activity during the grace period.