Here is the simple and low cost mosquito repellent circuit design. The circuit serves to keep the mosquitoes out of the room or the location where the device is installed. According to certain publications, the frequency emitted by the male mosquitoes is said to be around 20—25 kHz, and so within the realm of ultrasound.… Read More »
This is laptop / notebook protector circuit to protect your laptop or notebook or netbook from being stolen. Fixed in-side the laptop case, it will sound a loud alarm when someone tries to take the laptop. This highly sensitive circuit uses a homemade tilt switch to activate the alarm through tilting of the laptop case.… Read More »
Here the notebook anti theft protector circuit to secure your important netbook / notebook from stealing. Basically, this is a mini security alarm generator. Fixed inside the notebook case, it will definitely sound a noisy alarm when a person attempts to grab the notebook. This very sensitive circuit utilizes a homemade tilt switch to turn… Read More »
The following diagram is a simple mobile phone battery charger circuit. The design is simple, easy to build and inexpensive. It use LM78xx regulator to make regulated and stable output voltage. Mobile phone chargers offered in the marketplace are quite expensive. The circuit shown right here shows up as a low-cost option to charge cell… Read More »
This is definitely an ultra-sensitive fire sensor that exploits the direct piezoelectric property of an ordinary piezo component to recognize the fire. The lead zirconate titanate crystals within the piezo component have the property to deform and produce an electrical potential when heated, thus converting the piezo component into a heat sensor. The circuit mentioned… Read More »
The following diagram is the circuit diagram of simple 4W audio amplifier based TDA1013B. The amplifier is based on integrated audio amplifier chip, TDA1013B which is able to gained the audio power output up to 4W at 8 ohm loads. Wide supply voltage range can be used for this circuit from 10VDC to 40VDC. Recommended… Read More »
This is a 12VDC to 9VDC converter circuit. You may use this DC to DC stepdown converter circuit if you have fixed 12V power supply / battery, but you need 9V power supply for your electronic devices. Scheme Diagram: Components List: R1________ 560 ohm, resistor C1________ 1000uF/16V, Electrolytic capacitor C2________ 100uF/16V, Electrolytic capacitor C3________ 330nF,… Read More »
This is a mini fm transmitter circuit. I think this is the simplest one. Simple, easy and of course… inexpensive… The supply voltage is between 1.1 – 3 Volts with power consumption is 1.8 mA at 1.5 Volts. This circuit should be able to cover 30 – 50 meters of range max. at 1.5 Volts.… Read More »