A random number generator includes a plurality of memory cells arranged in a series, a feedback processor for generating a feedback signal and for feeding the feedback signal into one of the memory cells, and a random number outputter formed to combine states of a group of at least two memory cells to obtain an output sequence. Devices are provided which are operable to use vibration to provide an alert to a wearer of the device, the device including a transmitterreceiver unit, a transmit button operably connected to the transmitterreceiver unit and at least one vibration device operably connected to the transmitterreceiver unit. The holder comprises a screen that is added at the end facing the engine. The control unit is adapted to, for each signal processing path, dynamically select an associated subset, in the following denoted active switch subset, of the plurality of mixer switches for operation in the signal processing path such that which of the plurality of mixer switches belong to said active switch subset varies in time. Also, a cathode depolarizer, or degassing agent, from the group of nitro-substituted aromatic compounds can be added to reduce the amount of gas produced during capacitor life.