Power Supply

LED in AC


It is easy to light an LED by directly connected to 220 volt AC. It can be indicator in AC devices or Bed lamp if White LED is used. If used as a Bed lamp, the circuit can be enclosed in a plug  with LED projecting out.

Caution : The circuit is directly connected to high voltage that can give a fatal shock if handled carelessly . Do not test or troubleshoot when connected to mains. 

Advertisements
Power Supply

Over Voltage Protector


This circuit can protect AC appliances. When the AC voltage in the mains increases above the set level , say 220 volts, relay triggers and breaks power from the appliance. Reconnects the appliance when the power returns normal.

Continue reading “Over Voltage Protector”

Power Supply

Simple Power Failure Alarm


Beep once when power fails. 12 volt relay is used as a switch. When power is available, relay pulls and capacitor charges via diode D1 and NO and Common contacts of relay. When power fails, relay turns off and capacitor discharges via Common and NC contacts and buzzer. Buzzer gives a short beep at that time. If more timing for beep is needed, connect one more 4700 capacitor parallel to C1. 12 Volt DC for the circuit should be from a 12 Volt adapter or transformer power supply.

Utility Gadgets

Gas Leakage Alarm System


 

The Project implementing is a Gas leakage alarm system that senses the leakage of LPG from Gas cylinder or Gas stove and gives a warning alarm. Its further modification can be automatic cut off the electricity system in the home and also a battery operated exhaust fan to remove the leaked gas from the room.


Continue reading “Gas Leakage Alarm System”

Home Circuits, Techniques

PIR sensor based home surveillance system


This project is based on the PIR Motion sensor to detect human movement and alarm generation as a surveillance system for home and office. The circuit sends the alarm sound wirelessly to the interior of home and also switches on the outdoor lights when it detects a human movement. Continue reading “PIR sensor based home surveillance system”

Home Circuits

Alarm for Water Heater


It was a big problem in my house that, sometimes the Water heater left on for many hours after the use. It has a Thermostat to cut off but when the water cools, again it switches on. This causes hike in electricity bill. Finally I found a solution. Just connected a Timer based alarm with the heater AC socket so that it will also switches on when the heater turns on. After 30 minute, it gives a loud alarm to remind that the heater is On. Alarm continues for another 30 minutes or till the heater is switched off. So that alarm reminds to switch off the water heater. This can be used for Electric Iron also.

Continue reading “Alarm for Water Heater”

Articles, Battery, Circuit, Components, Design, Electronics, Home Circuits, How components work, Utility Gadgets

LED Emergency Lamp


Make this simple  White LED emergency lamp using few components. It can be plugged into the AC socket and it turns on at the moment when power failures. It emits cool white light in the room which is sufficient even for reading purpose. It is powered by a 4.5 volt rechargeable battery and uses 1 watt White LED.

Continue reading “LED Emergency Lamp”