Abstract: An audio/video (A/V) recording and communication doorbell, including a camera, a speaker, a microphone, a power manager, a battery, an AC/DC rectifier, and a DC/DC converter. The doorbell is configured for connection to an external AC power source through the AC/DC rectifier and the DC/DC converter. The power manager is configured to draw power, up to a threshold power, from the AC power source and to draw supplemental power from the battery such that the power drawn from the AC power source never exceeds the threshold power. The present A/V recording and communication doorbell can thus be connected to an existing household AC power supply and an existing doorbell signaling device without causing inadvertent sounding of the signaling device.

Abstract: A reversible short circuit device in the form of a metal loop. The metal loop has a first base side which forms a first contact. Extending from the base side are second and third generally parallel sides. The second side includes a contact portion for engagement with an external object to provide an electrical connection therewith. The second and their sides are connected by a frangible fourth connection side. One of the second and third sides is subject to a recoiling force, which, when the connection side is interrupted or broken displaces the contact portion of the second side so as to reverse the short circuit. The short circuit device has particular application to photoelectric tubes to provide a means for interconnection of the tube components during manufacture, which may subsequently be reliably disconnected.

Abstract: A thermally actuated switch having a bi-metal switch arm carrying a contact, a cooperating contact, a heating resistor and a holding resistor. The switch is enclosed in a sealed housing and circuit connections extend from the switch contacts, heating resistor and holding resistor to the exterior of the housing. The heating position thereby closing or opening the switch contacts, depending on whether the contacts are normally-open or normally-closed. After switch actuation, the heating resistor continues to supply heat to the switch arm to hold the arm in its actuated position. The connections from the heating and holding resistors to the exterior of the housing enable the connection of external variable resistors in circuit with the heating and holding resistors whereby the time required for the switch to actuate and the time to switch remains actuated may each be varied.

Abstract: A heater strip (12) is disposed in spaced relation to a temperature responsive actuator element (20) for indirectly heating that element in response to current flow in the heater (12). An adjustable heat sink (22) is disposed in spaced proximity to the actuator element (20) for removing heat from the actuator element by radiation therefrom through air to the heat sink in a first position and adjustable to be in thermally conductive engagement with the actuator in a second position for increasing the efficiency of heat transfer from the actuator to the heat sink. Increased current flow in the protected branch circuit is required to cause the actuator (20) to attain its predetermined actuation temperature as the heat sink is adjusted to increase the efficiency of heat transfer between the actuator (20) and the heat sink.

Abstract: A time delay relay has a switch assembly, a spring terminal assembly, and an electrical resistance heater unit of an inexpensive construction held together in a reliable and economical manner by a pair of easily mounted metal spring clips.

Abstract: The switch includes a generally J-shaped, bimetallic switch arm having two, spaced, parallel legs, one of which is longer than the other. The shorter leg is welded at its outer end to a metal boss, which is formed on the face of a mounting bracket, and thus supports the longer leg above the face of the bracket so that a first contact on the outer end of the longer leg overlies, and is normally engaged with, a second contact, which is mounted on said bracket to be insulated therefrom. The high expansion side of the switch arm faces downwardly to confront the bracket, and since the shorter leg responds more rapidly to temperature changes than the longer leg, it tends to resist movement of the longer leg between open and closed positions and thereby prolongs the time the switch arm remains in either position.

Abstract: An improved thermal switch permitting large temperature excursions beyond the design closure temperature without stressing the switch material beyond its elastic limits. It combines a bimetal portion with a spring portion through which movement is transmitted, the former providing sufficient deformation for closure at design temperature, and the latter accommodating excess deformation beyond closure caused by high temperature. It is particularly useful in metal halide lamps having gas filled outer envelopes and requiring shorting of an auxiliary starting electrode to the adjacent main electrode during operation.

Abstract: A current sensing, self-heating device for protecting equipment against abnormal current levels which is automatically resettable under mild overcurrent conditions and nonresettable under severe overcurrent conditions. The device comprises a thermostat metal assembly with a temperature compensating portion and an actuating portion which is placed adjacent a nonresettable two-position snap-acting blade electrically connected to ground. During normal operation current flows from the line source through the actuating portion of the thermostat metal assembly to the equipment. However, if an overcurrent condition occurs the heat generated in the actuating portion of the assembly will bend the assembly and cause it to make contact with the blade shorting the current from the line source to ground.