A microprocessor-regulated constant voltage, current, wattage, and temperature electrophoresis power supply

Abstract

The analog control circuitry typically found in commercial electrophoresis power supplies was replaced by a digital microcomputer. Analog to digital converters were used to monitor the voltage applied to and current passed through an electrophoresis cell. Microcomputer programming was employed to compare converter input values with preselected operating parameters and then calculate a required output voltage. Timing sequences were generated through programming utilizing clocks located on the interface boards. A digital to analog converter was employed to apply a control voltage to a constant voltage power supply. This process was completed at least 20 times each second. BASIC programming subroutines were written to maintain constant voltage, current, power (wattage), and temperature. To these operating procedures, other techniques such as automated endpoint detection of isoelectric focusing and pulsed waveform outputs were easily added. This power supply containing a microcomputer system as the feedback element was shown to have a greater stability and versatility than conventional supplies.