Category Archives: Misc



Small Sound Amplifier for Ears (Hearing Aid)

This is the simple project of small sound amplifier for ears or often called hearing aid device or hearing loss amplifier. This circuit was already tested on some patients and give significant improvement in the hearing ability to the patients. It consumes a very small amount of power within the range of 10 milliwatts. Furthermore,… Read More »

Low Cost Mosquito Repellent

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 »

12 Stage Water Level Indicator

The is a simple and versatile 12 stage water level indicator circuit which will show you the current water level in the tank. This circuit can be used for general purposes. This circuit generates an alarm when the water level is below the lowest level of L1 and also when the water just touching the… Read More »

Electronic Quiz Button Table

This is the circuit diagram of electronic quiz button table. This circuit is simple, easy to built and of course it is not expensive. This quiz circuit used for four game participants. It determines the contestant who first presses the switch (S1 through S4) to answer a question and locks out the remaining three entries… Read More »