PARROT-SOUNDING AC DOOR BELL
Here is a mains-operated door-bell that produces parrot-like sweet voice without requiring any musical IC. The circuit is cheap and easy to construct. The...
Circuit for UPS to Hybernate PC
Most of the low-power UPS systems available in the market do not have the facility to shut down the PC before they turn off...
LED Illumination for Refrigerators
The incandescent lamp provided inside the refrigerators glows whenever we open the door. It suffers from several disadvantages like:
1. Being a single light source,...
Electronic Reminder
This easy-to-build electronic alarm will remind you of an impotant task after a preset time. It is particularly useful for housewives and busy professionals....
Street Light Controller
Two of the problems commonly associated with street lights are false triggering due to slight variation in the intensity of ambient light and no control over switching action. Here is a simple switching circuit for street lights that overcomes these problem
AUTOMATIC EMERGENCY LIGHT
This emergency light has the following two advantages:
1. It turns on automatically when the mains power fails, so you need not search it in...
Simple Automatic Water-Level Controller
Water level controllers are common nowadays. The automatic water level controller described here is built around a timer NE555 and inverter buffer CMOS IC...
PROGRAMMABLE DOOR- BELL WITH FLASHING LEDS
IC1 (NE555) is used here as a clock generator. It is configured as an astable multivibrator whose frequency can be adjusted with the help...
SHORT WAVE TRANSMITTER
This transmitter circuit operates in shortwave HF band (6 MHz to15 MHz), and can be used for shortrange communication and for educational purposes.
The circuit...
Auto Reset Over/Under Voltage Cut-Out
This over/under voltage cut-out will save your costly electrical and electronic appliances from the adverse effects of very high and very low mains voltages.
The...