Abstract: An electronic display having a plurality of digit positions is employed in conjunction with a keyboard to enter data for controlling the operation of a microwave oven. Each digit position of the display is individually responsive to a corresponding key of the keyboard, whereby actuating such key causes its display digit to run repetitively through a numerical sequence without carrying over into other display digits. Upon stopping actuation of such key, its display digit stops on the numeral displayed at that moment. Other digits of the display may be similarly loaded with data, whereby the fully loaded display represents a control parameter, such as cooking time. Actuating a start key permits the oven to carry out a cooking program in accordance with the data thus entered into the display.

Abstract: A power supply for providing two different DC voltages from a transformer having a center tapped secondary winding is disclosed. An arrangement of diodes and capacitators forming a voltage doubler is connected to the secondary winding to provide a low DC voltage from the center tap approximately equal to one half of the RMS voltage across the secondary winding, and a higher DC voltage greater than twice the RMS value of the AC voltage across the secondary winding of the transformer.

Abstract: Circuitry for converting the nominally 600 hertz output of a gasoline engine driven magneto to 60 hertz. A pair of oppositely poled controllably enabled full wave rectifiers is connected to the magneto and the load. A zero crossing detector is coupled between the magneto and a counter. A rectifier control circuit is responsive to the counter output for controlling which of the full wave rectifiers is enabled.

Abstract: A battery charging system includes a circuit for sequentially connecting each of a plurality of banks of batteries to a constant current generator for a first predetermined period of time, for example, one hour, and then disconnecting all banks for a second predetermined period of time, for example, fifteen days. A plurality of controlled switching devices are sequentially gated to connect sequentially the banks of batteries, each for the first predetermined period of time, between the output terminals of a constant current generator. For n battery loads, the controlled rectifiers are gated by n outputs of a counter/decoder circuit having n + 1 outputs. The counter/decoder circuit is operated by clock pulse signals supplied thereto by a counter/time base circuit.

Abstract: Circuitry operating as a time delay/holding relay whereby a connection is established between a pair of output terminals whenever power is applied between input terminals and for a timed period after the receipt of a predetermined signal. A first integrated circuit is connected as a free running multivibrator to generate a pulse train for maintaining a bilateral thyristor in its conductive state to close the connection. A second integrated circuit, identical to the first, is utilized to enable the first integrated circuit. The second integrated circuit is connected as a free running multivibrator but oscillations are disabled until the receipt of the predetermined signal. This maintains the enabling signal for the specified time period after the signal is received. External connections of components to the second integrated circuit changes the internal operation of that circuit.

Abstract: A regulator circuit provides a constant direct current to a load, for example, a string of batteries. The current is regulated to be independent of the load and supply voltage variations and can be operated under open or short circuited load conditions for an indefinite time without damage. The generator includes a pair of SCRs in a full wave current supply which provide phase angle controlled current through the load and a sensing resistor in series therewith. The voltage drop across the resistor, which is proportional to the output current of the generator, is averaged by an RC network and compared with a reference voltage to develop an error signal which is amplified and conditioned to control the firing angle of the SCRs. Additionally, the regulator functions to supply a constant voltage output across the resistor.