Use the PowerPac Basic Power Supply for applications such as mini and midi vertical gel and submerged horizontal electrophoresis, and blotting using the Mini Trans-Blot® Cell. The power supply is fully programmable for either constant current or voltage, and either timed or untimed.
To prevent damage to electrophoresis cells, the PowerPac Basic Power Supply has automatic crossover. When the set limit of the nonconstant parameter (either voltage or current, depending on settings) is reached, and the power capability of the unit is not exceeded, the power supply will make the nonconstant parameter the new constant parameter.
Source: https://www.bio-rad.com/en-ph/sku/1645050-powerpac-basic-power-supply?ID=1645050