Many reed switches can be wired in series to perform na efficient alarm as shoen in the figure. Power supply must be 2 V highr than the coil of the relay to compensate voltage fall in the SCR. Current drain is very low when the relay is off.
![](/images/sampledata/cb/cb885_0001.png)
Many reed switches can be wired in series to perform na efficient alarm as shoen in the figure. Power supply must be 2 V highr than the coil of the relay to compensate voltage fall in the SCR. Current drain is very low when the relay is off.