High-Intensity, Energy-efficient LED Light
Here is a rechargeable LED lamp that gives you bright light for a long duration of time as it consumes little power. The circuit presented here is compact, automatic, reliable, low-cost and easy to assemble. More >
Four-Stage FM Transmitter
This FM transmitter circuit uses four radio frequency stages: a VHF oscillator built around transistor BF494 (T1), a preamplifier a preamplifier built around transistor BF200 (T2), a driver built around transistor 2N2219 (T3) and a power amplifier built around transistor 2N3866 (T4). A condenser microphone is connected at the input of the oscillator. More >
Mini Emergency Light
This is an LDR based Emergency Lamp that turns on a High watt White LED when there is darkness in the room. It can be used as a simple emergency lamp in the child’s room to avoid the panic situation in the event a sudden power failure.It gives ample light in the room.
Tilt Sensor Alarm Circuit
Ultra simple circuit of the tilt sensor alarm presented here can be fabricated using readily available inexpensive components. The circuit is a true transistor based design. Home made Tilt sensor for this circuit is an ordinary little glass/plastic bottle with two metal needles inserted through its cap, and a small quantity of water inside. More >
Electronic Gate Keeper
This circuit can do the job of a Gatekeeper and intimates you if someone passes through the gate. The alarm can be an AC bell or a Lamp. The alarm turns on for 1 minute and stops if the light barrier is restored again. More >
Electronic Card- Lock System
The circuit presented here can beused as a lock for important electronic/ electrical appliances. When card is inserted inside its mechanism, depending upon the position of punched hole on the card, a particular appliance would be switched on. More >
Four-in-one burglar alarm
Four-in-one burglar alarm In this circuit, the alarm will be switched on under the following
four different conditions More >
wireless car alarm
This FM radio-controlled anti- theft alarm can be used with any vehicle having 6- to 12-volt DC supply system. The mini VHF, FM transmitter is fitted in the vehicle at night when it is parked in the car porch or car park. More >
Audio Voice-Over any other audio
This is a circuit where a microphone and preamp circuit (voice circuit) have priority over any other audio signal. You can think of this as a one way intercom, if the main amplifier is used for listening to music, then when the push to talk switch is pressed, the amplifier is switched to the voice signal. More >
Metal Detector
A single chip metal detecor with a range of a few inches. This is useful for decting nails or screws in walls and floors, or for locating buried mains cable. More >