Patent attributes
A method and a control unit (4) for controlling a supply of power to an electrical circuit comprising a switch (3). An output voltage of a first power source (5), which is connected to the circuit, is measured and compared to a predefined threshold voltage. If the measured voltage is smaller than the threshold value it is determined that the switch (3) is in a closed state, and if the voltage is larger than the threshold value it is determined that the switch (3) is in an open state. The supply of power is controlled in accordance with the open/closed state of the switch (3). Preferably, the electrical circuit is connected to a second power source (9) when the switch (3) is in a closed state. Power is conserved while it is ensured that sufficient power is available when needed. The invention is very suitable for supplying power to a lamp (1) positioned inside a refrigeration compartment (2), especially when the system is battery powered.
