System of automatic inclusion and switching off of lighting
Now in the market there are ready schemes of inclusion and shutdown of lighting, and even with motion sensors. In many houses on landings it is possible to see how these schemes work. To try to make something similar it is possible also the hands.
Let's consider the device of the photoswitch intended for inclusion of lighting and shutdown depending on time of day (i.e. natural lighting). The scheme of the avtomatiyochesky switch is provided on fig. 1. The sensor of the fotovyyoklyuchatel is the fotosoprotivyoleniye F, as the izmeritelyyony scheme the full-wave circuit is applied. The sensor reacting to the size of outside lighting is located in one of shoulders of the izyomeritelny bridge of AG posledovayotelno with the semiconductor valve of 1VP. Other shoulder of BG included the winding of the neutral relay 2P, shoulders of the WB and AV obrazuyotsya by constants of the soprotivleniyayoma of R1 and R2. The closing contacts of the relay 2P are included in the upravyoleniye chain by lighting lamps of the Leningrad Region.
Measuring diagonal soyostoit from R3 resistance, posleyodovatelno to which the winding of the polarized relay 1P and the gas discharge tube MN are connected, payorallelno to the lamp of MN and the relay 1P the condenser C is connected. The IP relay is supplied with the throw-over kontakyot closing this or that chain (clips 1 i2) depending on the direction of current in its winding.
The power supply of the bridge is carried out through the valve of 2VP and through veryoshina of the measuring bridge of and Century. The gas discharge tube MN is the neon lamp in which cylinder under the small pressure (about ten millimetyor of the mercury column) there is the gas neon. The neon lamp has no heated cathode, and is supplied with two electrodes (in the form of plates, cylinders or delays). If tension on the lamp below the defined value called by tension the zazhigayoniya, then current does not pass through the lamp. At the tension equal to ignition tension, there is the ionization and through the lamp proyokhodit current. The neon lamp is always turned on through some resistance limiting current.
The scheme works as follows. If on the street light (illumination is higher than 10 lx), then current in measuring diagonal goes from the point of B to the point And, and polarized rele1r it is included in such a way that its throw contact is closed on the clip 1. The relay 2P is switched-off (the current passing through its winding is insufficient for operation of the relay); contacts of the relay are opened and consequently, lighting лампыЛО are disconnected.
Current in measuring diagonal goes from the point of B to the point And the potoyom that the potential of the point of B is higher than the potential of the point And, it follows from the fact that loss of tension on the shoulder of AV is more than loss of the napryayozheniye on the shoulder of the WB (that, in turn, is explained by sootvetstvuyuyoshchy selection of resistance of R1 and R2); besides resistance are connected to the same clip of the chain. It must be kept in mind that current passes in measuring diagonal not nepreyoryvno, and impulses, jumps. Gradually the condenser C zaryayozhatsya and tension on is mute increases; when tension on capacitor plates becomes equal to tension the zazhigayoniya of the gas discharge tube MN, the lamp is lit and passes current through the relay 1P winding. Thus, thanks to availability of the gas discharge tube in the chain of the relay will work more accurately and reliably at the defined value of tension (equal to the napryayozheniye of ignition of the gas discharge tube).
When illumination decreases, electric soprotivleyony the photo cell increases; thanks to it current in the shoulder of AV decreases and respectively also voltage drop decreases. As voltage drop in the shoulder of BV remains to constants, voltage drop in the shoulder of AV can become so small that potential in the point And will become big potential in the point of B, and current will change the direction and will begin to flow from And to B. Eto proyoizoydt when natural lighting by the evening decreases and there will be less than 10 lx. In process of reduction of illumination current will increase in measuring diagonal, tension on the konyodensator With increases also at its value equal the napryazheyoniya of ignition of the lamp of MN, the condenser will be discharged through the lamp and the polarized relay 1P in the opposite direction; the relay will throw the contact on zazhim2 (the scheme of the measuring bridge naruyoshatsya by it). At the same time the coil of the neutral relay 2P will be priyosoyedinenny to the full alternating current mains voltage of 220 Century. The relay 2P will work and short circuit of the contact will include osvetiyotelny лампыЛО. Thus with approach evening сумерек electric lighting automatically joins.
At approach of morning illumination increases, and the fotovyklyuyochatel has to disconnect electric lighting. Let's trace as it occurs. With increase in illumination the electrical resistance of the photo cell F in this connection the direct current passing on this shoulder (AG) uveyolichivatsya decreases. On the measuring diagonal of A B will pass constant (more true, pulsing) current on the following chain: the phase L2 - the clip 2 - B - And - 1VP - F - - the phase L1, besides, on the same diagonal will pass the alternating current forming the sleyoduyushchy chain: the phase L2 - the clip 2 - B - And - In - R4 - the phase L1.
So far illumination is small, the potential difference between points of B and And is insufficient for ignition of the lamp of MN and, as a result, for operation of the polarized relay 1P. In process of increase in illumination (it is higher than 10 lx) potential in the point And as it was already explained above, will appear less than the potential in the point of B; current will change the direction to the return, and the condenser C разрядится to the lamp of MN and the relay 1P from the point of B to the point And; the relay will work and will throw the contact on the clip 1. At the same time the relay coil 2P will be disconnected from full mains voltage of 220 V and sraboyotat on shutdown of the contact; electric lighting will be switched off.Top