Circuit Magnetic Proximity SwitchHere is an absorbing ambit for a alluring adjacency about-face which can be acclimated in assorted applications.
The alluring adjacency about-face circuit, in principle, consists of a reed about-face at its heart. When a allurement is brought in the around of the sensor (reed switch), it operates and controls the blow of the switching circuit. In abode of the reed switch, one may, as well, use a general-purpose electromagnetic reed broadcast (by authoritative use of the reed about-face contacts) as the sensor, if required. These tiny reed relays are calmly accessible as they are broadly acclimated in telecom products. The reed about-face or broadcast to be acclimated with this ambit should be the �normally open� type.
When a allurement is brought/placed in the around of the sensor aspect for a moment, the contacts of the reed about-face abutting to activate timer IC1 active in monostable mode. As a aftereffect its achievement at pin 3 goes aerial for a abbreviate continuance and food alarm to the alarm ascribe (pin 3) of IC2 (CD4013�dual
D-type flip-flop). LED D2 is acclimated as a acknowledgment indicator.
This CMOS IC2 consists of two absolute flip-flops admitting actuality alone one is used. Note that the flip-flop is active in toggle approach with abstracts ascribe (pin 5) affiliated to the Q (pin 2) output. On cancellation of alarm pulse, the Q achievement changes from low to aerial accompaniment and due to this the broadcast disciplinarian transistor T1 gets forward-biased. As a aftereffect the broadcast RL1 is energised.
