Abstract: An electrical apparatus comprising a first housing portion and a second housing portion, a first set of battery contacts and a second set of battery contacts, when the second housing portion is at a first relative position, the second set of battery contacts is at an actuation position; and when the second housing portion is at a second relative position, the second set of battery contacts is at a non-actuation position.

Abstract: A loudspeaker that can be bi-wired or not according to a user's preference comprises a case in which is provided a plurality of audio drivers supplied by a respective plurality of audio networks, the networks being supplied (in turn) by a respective plurality of input terminal pairs, further comprising at least one switch bridging the terminals of different pairs, and adapted to selectively connect the terminals to each other.

Abstract: An amplifier including a difference amplifier, said difference amplifier including a first output and a second output which are adapted for providing a PWM signal output to a load by signal difference between said first and said second outputs, said difference amplifier being adapted for operating in at least first and second alternative operating modes which are respectively characterised by first and second operating voltages, wherein during transition from one operating mode to another, the pulse area of the pulses of said first and second outputs of said difference amplifier are changed according to a pre-determined manner so that the pulse area of pulses of said first and second outputs at the end of said transitional mode is equivalent to the pulse area of the pulses of said first and second outputs immediately after the change of operating modes.