Abstract: The method described coats the interior of a tube-like support with the binding partner of the analyte. Analyte and anti-analyte-label conjugate are added. When the tube-like support is rotated end-over-end, the thin layer of analyte and conjugate readily react with the binding partners to form an immobilized label complex. When rotation stops, the reaction quenches to provide precise timing. The label complex is released and measured.

Abstract: The power control circuit described functions to vary the duty cycle of the alternating current signal supplied to the load. The duty cycle is varied by periodically generating a first signal, each half cycle of the alternating current signal, that is proportional to the actual power supplied to the load as a function of the duty cycle and wave form of the alternating current signal. A comparator compares this first with an error signal to vary the duty cycle in accordance with the power demanded by the error signal. The first signal is derived by evaluating the integral of the square of the voltage over each half cycle of the alternating current signal.