| 摘要 |
An indoor living space ambient temperature sensitive alarm system is able to detect relative temperature rise or fall and is arranged so that an alarm signal is only triggered after a delay period has lapsed and the temperature is found to be still dropping or rising. Figure 1 shows an example alarm circuit with thermistor sensor 3 feeding an operational amplifier which differentiates the input signal over a delay period set by RC pair 5, 6. The system may be a stand alone unit (fig 2, not shown) or may comprise remote sensors mounted on doors or windows (figs 3-6, not shown). The system may trigger a door bell sounder to play a particular chime as an alarm. The system may also log occurrences of alarm events. |
