Abstract: This invention relates to driving solenoid and motor loads while providing the means for fast turn on and fast turn off. Many applications including automotive fuel injector drivers, Anti-Skid Braking (ABS) solenoid and motor drivers, and other electro-mechanical motion control require the ability to quickly turn on or off a number of devices. The invention utilizes a bridge architecture to drive the loads and to turn on and off individual devices. The invention employs a diode and a switch for each device controlled plus a single master diode and a single master switch. The invention thereby reduces the number of components needed to control N devices to 2*N+2 from prior art half bridge circuit 4*N. Novel techniques and algorithms are used to multiplex the single master switch and control multiple inductive devices. The system provides redundant control and error checking means to preclude single point failure mechanisms.

Abstract: A method and apparatus measured and calculates the derived thermodynamic state of a heat-pump or air conditioning system using information from transducers sensing elementary thermodynamic variables in the system. Elementary signals such as pressure, temperature, power, humidity, air flow, and others as required are derived using transducers from closed and open portions of the thermodynamic system, and which signals are then transmitted using appropriate transmission media. These signals are input to a computer, which could take many forms (electrical analog, electrical digital, pneumatic, hydraulic, and others), and these signal inputs along with known and tabulated thermodynamic characteristics of the working fluid (refrigerant) and psychrometric properties of the cooled media (air for example), are used to calculate thermodynamic output variables such as entropy, enthalpy, pressure, temperature, and volume at various states in the thermodynamic cycle.

Abstract: The junction temperature rise of a power MOSFET serially connected to a lamp whose resistance nonlinearly increases during turn-on is moderated by the use of control circuitry which initially sets up a relatively low essentially constant current flow through the lamp and transistor and then automatically after the lamp resistance reaches a preselected level, the lamp is allowed to draw significantly more current. The size and therefore cost of the power MOSFET is reduced significantly because the magnitude of the current spike generated by turning on the lamp is significantly reduced the use of the novel control circuitry.

Abstract: Damping resistance is introduced via transformer coupling into a circuit which includes an inductance-capacitance (LC) filter arrangement to smooth the current pulses applied to a load.

Abstract: Disclosed in a differential operational amplifier for use with a proximity type pick up. It has a common mode rejection input circuit comprising a diode and transistor connected to each input as well as diodes connected across the amplifier differential inputs. Common mode signals are clamped at the input to both protect the amplifier and prevent false transitions at the output.

Abstract: Disclosed is a circuit for producing an alarm or shut down signal when the ratio of engine speed to engine oil pressure of a tractor engine becomes excessive. A frequency signal from a speed transducer is applied to a digital counter having a counting cycle varied in accordance with a voltage signal from a pressure transducer. The voltage signal is converted to current and used to determine the period of a one shot multivibrator.