Automatic Lighting System. Home Utility Circuit 6

downloadSave energy by installing an Automatic lighting system in your home. Connect the external lights to the system, so that it turns on the lights in the evening and turns off in the morning. No daily switching is needed and, it will light the premises of home even if nobody is there. It is too small and can be enclosed in a small plastic case.
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Sunset Lamp. Design Note 45


Many people leave the outdoor lights switched on as a safety measure while going for a long journey. The light will be on during day time also wasting lot of power and money. So here is a simple solution to avoid this. This circuit lights the premises of your home even if you are not there. It is fully automatic and turns on  Bulbs or CFLs at Sunset and turns off at Sunrise. So no need for daily switching. The circuit can run 250 watts load so many lamps can be connected. It is too compact and costs only Rs. 50 without power supply and the total cost will be around Rs.150. So once it is connected, we need not remember to switch on / off the outdoor lights. It will do its job at the right time.
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Automatic Porch Light. Utility Gadget.14

Here is a simple Automatic Porch light controlled by an LDR and Triac. It automatically turns on in the evening and turns off in the morning. The circuit is too simple and uses Mains voltage directly. It can be enclosed in a plug in type adapter box.
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How to remove Rate effect and Backlash effect from Triac? Solution File 1

Triacs are the most common semiconductor devices used in power control and switching applications. The electronic power control circuits are designed to control the distribution or levels of AC or DC power sources. Such power control circuits can be used to manually switch power to electrical devices or to switch power automatically when parameters such as temperature or light intensities go beyond preset level. Triacs are borne with some inherent drawbacks, which will reflect in their working.

Rate effect is the unwanted effect on triac controlled circuits caused by the transients in the AC line which causes erratic functioning of the circuit. Backlash Effect is seen in Lamp dimmer circuits using triac and sometimes the lamp never turns on when the control pot is turned fully. Here are the tricks to solve both the problems.

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Familiarize Electronic Components Part IV – SCR, TRIAC, DIAC

Modern power control systems utilize electronic devices like Thyristors for power switching, phase control, as chopper etc. These devices also find applications in inverter design, brilliance control in lamps, speed control of motors, Fan speed regulation etc. SCR, Triac and Diac are the members of the Thyristor family.

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Transil, Trisil and SIDAC

Transil is the trade name of Transient Voltage Suppression diode or TVS diode of ST Microelectronics, Transil diode is used to protect sensitive electronic devices from voltage spikes and transients induced by the mains. Transil protects the circuit by shunting excess current if the induced current exceeds the avalanche breakdown point. It works like a clamping diode to remove all the excess voltage induced. When the overvoltage condition goes off, the Transil automatically resets. Trisil is the trade name of the Thyristor Surge Protection device, another surge protector for electronic equipments. SIDAC is also a protection device less commonly used for surge protection for AC.

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