switches can also be increased. One of the good quality of the circuit is that it can cover a large area therefore you can increase the length of the wire to increased the number of doors.
The circuit is using fewer components and can be built easily in short period of time. The hear of the circuit is a famous 555 timer IC. A relay switch is connected at the output of the IC, from which you can connect any AC or DC bulb for visual indication. You can also connect any AC or DC alarm with it for example a doorbell. The operating voltage of the circuit is 9V to 12V DC. It can also be operated the voltages below 9V but it is must to use a same voltage relay.
This simple multiple door open indicator circuit can be used to detect or monitor if any door has left opened. The circuit can be used for variety of purposes for example door security. The circuit using three normally closed reed switches, which can be places on desired doors. The number of reed
Hello Readers, We frequently add new circuit diagrams, so do not forget to come back often. Thank you.