Abstract: A flame detector, for use with a photocell which produces a flame signal when the photocell is exposed to a flame, is used for detecting the presence of a flame. An input circuit is coupled to the photocell for receiving and buffering the flame signal. The buffered flame signal is filtered and amplified in a filter. An output circuit further amplifies the filtered flame signal providing an output flame signal. A switch is also used in the flame detector for substantially short circuiting the flame signal to a known value upon receiving a switch-close signal from either a test computer or from a hot refractory detection circuit. A flame-out condition is detected by the hot refractory detection circuit which generates an HRD signal causing the flame signal to be substantially short circuited to a known value thereby eliminating a false flame signal caused by hot refractory shimmering.

Abstract: A battery-powered medical treatment inductor coil generates a pulsed current inducing a magnetic field in the inductor coil for interaction with the patient's body. At the end of a pulse, the magnetic field collapses and an energy recovery circuit returns the energy in the collapsing field to the battery to reduce its average drain thus prolonging battery life.

Abstract: A random signal isolation circuit connectable to a source of signal generation wherein signals of interest tend to occur at relatively closely spaced intervals, and noise signals tend to occur at random time intervals, including a first multivibrator trigger circuit which triggers on the falling edge of a received signal, and a second multivibrator trigger circuit which triggers on a rising edge of a received signal, the first multivibrator circuit being connected when triggered to enable the second multivibrator trigger to receive subsequent received signals. The first multivibrator trigger circuit is activated over a predetermined time delay, and at the end of the time delay disables the second multivibrator trigger circuit.

Abstract: A molded plastic housing mounts a coil adjacent to a conductor to act as a current responsive pickup means. The mounting arrangement for the pickup coil uses no magnetic circuit and is adapted to self-center the structure on conductors of varying sizes without the need to sever and reconnect the current carrying conductor. The pickup means provide a substantially linear output voltage from the pickup coil versus the current being carried in the monitored conductor.

Abstract: An intermittent gas pilot system utilizing a flame signal simulating circuit means provides for both dynamic as well as static safe start checking for the system. A simulated flame signal is provided so that the relays contained within the system must be checked dynamically before the system will allow the opening of the main gas valve.

Abstract: A temperature control system for a building has a temperature responsive means or thermostat in the space for controlling a temperature conditioning apparatus furnishing temperature condition medium to the space. A time control apparatus provides for a reduction or deviation of the space temperature during certain time periods for the purpose of energy conservation and/or comfort. The space temperature is restored to the normal temperature by a pickup operation. The magnitude of temperature setback initially selected or to be maintained during the setback time period is automatically adjusted by responding to the actual building heat load, so as to keep the time and heating capacity needed to restore the space to the normal temperature within certain limits.

Abstract: An energy saving thermostat adapted to be connected to a remote temperature conditioning apparatus for controlling the temperature of air in a space maintains a first temperature during a first time period and a second energy saving temperature during other time periods of the day. The thermostat has a visual indicating means so that when a manually settable switch is pushed, a time interval counter means is energized for indicating and storing a series of pulses each indicative of an hour of setback time into a storage means. The thermostat also has a review button for reviewing the stored time by pulsing the visual indicating means for the number of hours of the time period energy saving temperature.

Abstract: An electronic switching circuit is provided for controlling transfer of electrical power from an alternating polarity electrical power supply to a load means through use of a field-effect transistor device as the primary power controlling element.

Abstract: An ionizing type smoke detector device has an output voltage which is compared with a reference voltage and upon the output dropping below the reference, a horn is energized. The reference voltage is normally quite low to reduce the number of false alarms and thus the smoke detector is relatively insensitive to smoldering fires which may require a high sensitivity of the smoke detector device. A timer means periodically modifies the reference voltage to a high value for a short period of time to make the smoke detector more responsive to smoldering fires and yet with the higher sensitivity for the short period of time the number of false alarms are kept at a minimum. Additionally a counter circuit is provided for counting the outputs of the smoke detector over three timing periods and if an output exists for three consecutive periods, an output to the horn is provided.

Abstract: A condition control system utilizing a digital display arrangement is disclosed. The system provides for a digital input of the setpoint of the system, and a digital display to display the setpoint selected for the system. The system also measures the controlled condition and provides a digital display of the output. The system provides further that when the controlled condition is within a predetermined or preselected range of the setpoint condition, that the digital display is caused to display the setpoint value even though it may be slightly different than the actual sensed value.

Abstract: A special regulating type of transformer is used to energize a hot surface igniter, a fuel valve and a fuse in a series circuit. The design of the regulating transformer is such as to provide an operating current in the igniter and valve that will not blow the fuse as long as the igniter is neither short-circuited, nor heated to a level which would be destructive.

Abstract: A condition responsive element, disclosed as a negative temperature coefficient thermistor, operates in conjunction with a bridge circuit to provide a differential input to a special direct current amplifier system. The amplifier system utilizes a combination of positive feedback and negative feedback with the negative feedback always exceeding the level of the positive feedback under steady state operating conditions. The output of the amplifier means further is connected to the lowest energizing potential for the amplifier means through a network that includes a relatively fixed voltage dropping means so that changes in the negative feedback can be made to change the gain of the amplifier system with a minimum of offset or change in calibration of the condition responsive device.