To provide a gas alarm unit which can be used for both domestic and commercial purposes via the switching of alarm systems.
An alarm unit includes a sensor circuit part 1 which outputs an alarm command 1s after detecting that the density of the gas 10 to be detected exceeds a fixed level, an alarm tone storage part 2 which previously stores the alarm tones as signals and outputs an alarm tone signal 2s after reception of the command 1s, and an alarm output part 3 which converts the signal 2s into an alarm tone 3s and outputs it. In such a constitution, the part 2 previously stores plural types of alarm tone signals that can be selected and a changeover switch 4 is added to supply the command S1 to the part 2 as the selection signals 1SK and 1SG for those alarm tone signals.
YOSHIMURA MASAHIRO
HIROSE MINORU
OCHIWA SHINICHI
FUJI ELECTRIC CO LTD