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...
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...
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...
Highway Alert Signal Lamp
Here is a signal lamp for safe highway driving. The lamp automatically emits brilliant tricolour light when a vehicle approaches the rear side of...
Doorbell-Controlled Porchlight
This add-on circuit automatically turns on your porchlight when your doorbell rings, so you can see the person ringing the doorbell at the doorstep....
Intercom with Musical Ringtone
Here’s a low-cost two-way intercom circuit with musical ringtone that can be made using readily available components (see Fig. 1).
Melody generator IC UM66 (IC1)...
Ultra-Bright LED Lamp
This ultra-bright white LED lamp works on 230V AC with minimal power consumption. It can be used to illuminate VU meters, SWR meters, etc....
Electronic Scoring Game
You can play this game alone or with your friends. The circuit comprises a timer IC, two decade counters and a display driver along...
Telephone Line Based Audio Muting and Light-on Circuit
Very often when enjoying music or watching TV at high audio level, we may not be able to hear a telephone ring and thus...