Power Resumption Alarm and Low Voltage Protector
The low voltage protector circuit described here protects your electrical appliances like AC motors from damage due to low voltage at power-on. It remains...
Night Alert System
Idea of this night alert system came to me one midnight when my pet dog started barking continuously on sensing a moving shadow, perhaps...
USB Power Socket
Today, almost all computers contain logic blocks for implementing a USB port. A USB port, in practice, is capable of delivering more than 100...
Skin Resistance Meter
Human skin offers some resistance to current and voltage. This resistance changes with the emotional state of the body. The skin resistance meter circuit...
Remote Operated Switch
Generally, a bedside master switch is used to switch on lamps both indoors and outdoors when there is a threat of intruder. This remote...
Fully Automatic Emergency Light
This is a circuit for an emergency light that automatically turns on when the supply is gone and turns off when supply resumes. It is rechargeable and stops charging the battery when the battery is full.
PC Timer
Primarily intended for installation into a desktop PC, this versatile PC timer with adjustable time output provides controlled ‘on’ time for PC peripherals like...
Automated Alarm Circuit
Two automated alarm circuits are presented here. One produces bird-chirping sound and the other British police siren tone. Fig.1 shows the circuit of the...
Multipurpose Power Pulser
The idea behind this multipurpose power pulser is very simple. As shown in the circuit (Fig. 1), it uses a low-frequency oscillator to drive...
Midnight Security Light
Most thefts happen after midnight hours when people enter the second phase of sleep called 'paradoxical' sleep. Here is an energy-saving night security light...
