Little Door Guard
If some intruder tries to open the door of your house, this circuit sounds an alarm to alert you against the attempted intrusion.
The circuit...
Power Failure And Resumption Alarm
This circuit gives audio-visual indication of the failure and resumption of mains power. The circuit is built around dual timer IC LM556. When mains...
Solar Bug
This Solar Bug circuit takes power from a small solar panel and then produces a sound in a buzzer momentarily when the relaxation oscillator...
Accurate Foot-Switch
Certain industrial controls require accurate switching operations. For example, in case of a foot-switch for precise drilling work, even a small error in switching...
Power-on Reminder with LED Lamp
Many a times equipment at workstations remain switched on unnoticed. In this situation, these may get damaged due to overheating. Here is an add-on...
Digital Audio/Video Input Selector
Need to connect more than one audio-video (AV) source to your colour television? Don’t worry, here’s an AV input expander for your TV. It...
Multiple Applications of High-Power LEDs
Nowadays, high-power light-emitting diodes (LEDs) LXHLMW1C are available in the market. These white LEDs contain indium-gallium-nitrogen (InGaN). The LEDs’ emitting capacity is 20 candela...
Pencell Charge Indicator
Small-size AA cells and button cells used in electronic devices providing a terminal voltage of 1.5V are normally rated at 500 mAh. As the...
9-Line Telephone Sharer
This 9-Line Telephone Sharer circuit is able to handle nine independent telephones (using a single telephone line pair) located at nine different locations, say,...
Audio Amplifier for Personal Stereo
In the output stages of most broadcast receivers and some amplifiers, there is a limit up to which maximum power can be developed without...