Hematocrit measuring apparatus

Claim 1

Hematocrit measuring apparatus comprising: cell sizing appaRatus for producing over a measurement period electrical pulses having amplitudes directly proportional to the volume of individual cells said pulses having leading and trailing edges; means for summing the amplitudes of all of said pulses during said measurement period including first storage means responsive to said leading pulse edge for sequentially storing the amplitudes of said pulses, second storage means coupled to said first storage means for accumulating said sequentially stored amplitudes of said first storage means, means responsive to said trailing edges of said pulses for transferring said stored amplitudes of said first storage means to said second storage means said transferring means including a first transistor for providing a charge transfer path from said first storage means to said second storage means said first storage means including an operational amplifier, a second transistor, and a capacitor, the base of said second transistor being coupled to the output of said amplifier so that the leading edge of a pulse places said second transistor in a conductive condition to charge said capacitor to the peak amplitude of said pulse, said output of said amplifier switching polarity in response to said trailing edge of said pulse for turning off said second transistor and turning on said first transistor whose base is coupled to said output.