Zero inrush alarm circuit

An alarm unit comprising:

• means for producing a visual alarm signal comprising a flashtube, first means for storing energy supplied from a power source and second means for storing energy to be supplied to said flashtube, the first and second energy-storing means being electrically connected in series;
• first switch means connected in series to the first energy-storing means and having a first state in which energy is stored in the first energy-storing means and a second state in which energy is transferred from the first energy-storing means to the second storing means;
• inrush-limiting resistance means connected in series with the second energy-storing means;
• second switch means having a first state and a second state, the second switch means being operatively coupled to the inrush-limiting resistance means such that, in the first state thereof, current flows through the inrush-limiting resistance means and, in the second state thereof, current does not flow through the inrush-limiting resistance means;
• first means for controlling the operation of the visual alarm signal producing means;
• and
• second means for controlling the operation of the second switch means so that the second switch means is in the first state for a time period sufficient to minimize inrush to the second energy-storing means.