Appendix; Ohm's Law Conversions - VWR 700-0450 Manuel D'instructions

APPENDIX

Ohm's Law Conversions

Electrophoresis is the migration of a charged particle under the influence of an
electrical field. The power supply output parameters voltage, current, and power are
related by the following two equations:
Voltage (V) = Current (I) x Resistance (R); (V=IR)
Power (W) = Current (I) x Voltage (V); (W=IV)
Resistance
Resistance of the assembled electrophoresis cell is dependent on the conductivity of
the gel buffer, the thickness of the gel, and the number of gels being run. Although the
resistance is determined by the gel system, the resistance can vary over the course of
an electrophoretic separation.
Voltage
The velocity with which an ion moves in an electric field will vary in proportion to the
field strength (volts per unit distance). The higher the voltage the faster an ion will
move.
Current
Current is a function of the number of ions passing a given cross-section of the circuit
at a given time. For a given gel/buffer system, at a given temperature, current will vary
in proportion to the field strength (voltage) and/or cross-sectional area (number and/or
thickness of the gels).
Power
The power in Watts, or the rate of heat generated by the system, is directly
proportional to voltage and current (W=IV).
15