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...
Solidstate Remote Control Switch
Here is a solidstate remote control switch which uses readily available electronic components. The control circuit comprises the transmitter and receiver sections. The range of...
