Abstract: An electronic selector knob circuit (10) which uses a tapped potentiometer (POT1) to provide accurate operation without requiring factory calibration. The potentiometer (POT1) is calibrated through on-board circuitry which includes a tap voltage biasing device and which monitors operation on a continual basis through both a current monitor (16) and a voltage monitor (18). A redundant disable circuit (14) provides a redundant hardware means for shutting off all oven heating elements.

Abstract: A controller for a relay controls the pull-in time of the armature of the relay by controlling the power applied to the relay coil. To determine the actual pull-in time, the time of closure of the contacts is sensed and the time at which power is applied to the coil is subtracted from it. The actual pull-in time is then compared with a stored value of ideal pull-in time to produce an error signal. The error signal corrects the level of power applied to the relay coil upon the next actuation of the relay, to make the actual pull-in time approximately equal to the ideal pull-in time. In some embodiments to control the level of power on the coil, a Gray-code counter samples a duty-cycle register in a micro-computer and produces a train of pulses that is filtered to provide a DC control signal. The DC control signal controls the duty cycle of a pulse-width-modulated oscillator that rapidly switches (modulates) the power to the relay coil.

Abstract: Apparatus and method for retaining an electronic device having an encapsulated body portion of a generally uniform cross section by means of a socket assembly having a plurality of deformable ribs extending medially therein. The electronic device, in particular an LED is inserted into the cavity for frictional retention therein by deformably engaging the ribs of the socket assembly. Critical height spacing of the LED is retained yet the deformable ribs allow for thermal expansion and contraction of the device body and leads without placing undue stress on its lead/die interface.

Abstract: A visual display mounting assembly is provided wherein a substantially rectangular parallelopiped central body 18 of a display module 17 is sandwiched between a planar surface 29 of a printed circuit board 23 and a substantially planar chassis wall 15 having a rectangular opening 16 therein for a front viewing surface 19 of the display module. The chassis wall opening 16 is formed with two opposing planar edge portions 32 of the chassis wall and two opposing nonplanar edge portions 33 of the wall comprising bent portions of the wall projecting towards the module. Peripheral portions 34 of the front surface 19 of the display module are positioned in pressure contact with the planar edge portions 32, and the front surface 19 is positioned between the non-planar edge portions 33 of the chassis wall. The display module 17 is held in place by retaining twist tabs 24 fixing the circuit board to the chassis wall and thereby having the circuit board press the display module body against the chassis wall.

Abstract: A sequencing control circuit is provided for a door operator motor which is connected to open and close a garage door as controlled by signals from manual switches and load switches. The sequencing control circuit includes time delay means with a first time delay period in the order of six to eight seconds. This permits a person to hold a push button switch closed for about six to eight seconds so that a slab door may be opened against a snow drift which otherwise would have so much torque requirement on the motor that an overload switch would stop the motor. Enabling means is provided to enable the motor during this time period yet to disable the constant signal from the push button for periods longer than this time delay period so that the door operator motor then is responsive to signals from the load switches.The sequencing control circuit also includes a latch circuit having an output in a feed back loop to maintain the latch circuit latched upon a momentary input control signal.