Choosing Limiting Parameter Settings - VWR Power Source 300V Manual Del Usuario

On the Display Screen:
•
• The chosen constant parameter (Voltage or Current) is displayed in bold on the left side of the
display.
The Timer is the first line on the right-top, and the non-constant value is displayed in
•
the second line on the right side of the display screen.

Choosing Limiting Parameter Settings

The 300V Power Supply is capable of operating at limiting voltage, or limiting current. We
recommend operating the 300V Power Supply at limiting voltage for most applications. See
below for more details.
Voltage Limiting
For most electrophoresis
provides the following advantages:
The same voltage setting can be used regardless of the number or thickness of gels being
•
processed.
• Current and power output decrease throughout the run, providing a greater margin of safety
over time.
Current Limiting
Discontinuous buffer systems and, to a lesser extent, continuous systems increase resistance
during the run. If you use the current limiting setting on the 300V Power Supply, the voltage will
increase as resistance increases to satisfy Ohm's law (V=IR). If no voltage limit is set and a
local fault condition occurs, such as a poor connection, very high local resistance may cause
the voltage to increase to the maximum capacity of the power supply. This may lead to local
overheating and damage to the electrophoresis running tank or create unsafe conditions.
When operating under constant current conditions, set a voltage limit on the power supply at or
slightly above the maximum expected voltage.
Basic Constant Operation Protocol
The Constant Voltage and Constant Current Modes allow you to specify a voltage limit, and
current limit to be used continuously during the entire duration of electrophoresis. Review the
guidelines provided in this manual before starting electrophoresis.
A basic Constant Voltage / Current Mode operating procedure of the 300V Power Supply is
provided below. We recommend reading the guidelines provided in this manual for best results
before starting an operation.
1. Use the power switch on the rear side of the instrument to turn on the 300V Power Supply.
1/28/2015
Revision 1.0
methods, resistance increases during the run. Limiting the voltage
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