Abstract: Current flowing into and out of a battery installed in a vehicle (V) with the required cable between one of the battery terminals and a reference point on the vehicle is determined by measuring the voltage across the cable and computing the current from the digital value of the measured current. The resistance value of the cable can be known in which case the current is computed using Ohms law and a differential current sensor can be used to respond to the voltage measured across the cable to accommodate for different ranges of current. In an embodiment where the cable resistance is unknown, a reference current source produces a known voltage that is used to set the input value to an amplifier of fixed gain for the voltage measured across the cable by controlling the output of a potentiometer so that the amplifier output voltage can be set to match the reference current generator output voltage, thereby establishing the voltage output of the amplifier as a measurement of the current flow in the cable.

Abstract: A hematology analyzer for counting red blood cells and white blood cells wherein separate counting heads and circuits are provided for counting each type of blood cell. Tests may be run separately or simultaneously during the counting operation. The operation of each head is optimized, thereby yielding greater reliability, precision, accuracy, speed, and efficiency. Electronic circuitry generates pulses as each cell passes through a sensing zone. A real time display of these pulses is provided on a cathode ray tube display.

Abstract: A system is provided to permit the independent, simultaneous operation of several model railroad train sets along a single track at variable speeds and in the forward and reverse direction, as desired. The system employs apparatus for generating a repetitive ultimate duty cycle and for dividing the duty cycle into spaced apart timewise time slots. During each time slot a train driving voltage of preselected polarity and amplitude is applied to the track. Time gaps are provided between the time slots and during each such gap a control signal of predetermined frequency is applied to the track. The system further includes a sensor mounted in each train and connected to the dc motor of the train. Each sensor is tuned to one of the predetermined frequencies and includes a latching circuit responsive to its frequency which latches the dc motor to the track during the immediately following time slot. The duty cycle and time slots are chosen to permit the trains to operate smoothly and without interruption.