Simple FM Transmitter Circuit Schematic

This is a simplest FM transmitter circuit schematic with a single transistor. It build with a very few numbers of components include a transistor, few capacitors, resistors and a small microphone.

Clap Switch Circuit Diagram Project

This is a simple clap switch circuit diagram project. If you are a beginner electronics learner, and love to do new project experiment then this is a great circuit for you.  This circuit can on/off a 220V electronic device like fan, lamp by the sound of clap.

Circuit diagram of clap switch

Water Sensor Circuit Diagram using IC 555

This is a water sensor /rain alarm circuit diagram; it can be used on motorcycle, car or other device that we want to protect from water, rain.
This is a simple water sensor/rain alarm circuit that makes an alarm when water/rain falls on its sensor. This circuit is based on NE555/LM555 IC and two transistors (Q1&Q2). For  transistor Q1- BC547 or BC107 and for Q2-  2N825,BC548 or BC168 can be used in the circuit. This rain detector circuit can be supplied from voltage source of +9V-12V DC. The resistor 470K ohm is a POT/Variable resistor; it is used to adjust the sensitivity of water/rain sensor. Use a 8 ohm,0.5w-1W  speaker to hearing  better alarm. Less than 8 ohm speaker could be harmful for the IC 555.

Circuit Diagram of Water Sensor

Fig-1: Water Sensor/Rain alarm circuit diagram

Ultrasonic Mosquito Repeller Circuit Diagram by CD4017

This is a simple ultrasonic mosquito repeller circuit diagram. The circuit is design on the theory that pests like mosquito can be repelled by ultrasonic frequency around (20KHz-25KHz). This ultrasonic mosquito repeller circuit is based on a single CMOS IC CD4017. C1,R1 & VR1 is used to adjust the output frequency.

Circuit Diagram:

Fig: Ultrasonic mosquito repeller circuit diagram

Song-Music generator circuit using ic UM66

This is a simple (song) music generator circuit using ic UM66. To make a musical calling-bell, door-bell, kids toys etc. we can use this funny audio/sound/music/tone generator ic UM66. The UM66 series are CMOS IC’s, they has a built in ROM to store the music. The IC operates in DC +3V. We suggest to use two dry cell (1.5V X 2) for +3V Supply.  For Q1 use a TO-92 type NPN transistor like BC548, BC168, BC183, BC238, 2N2222. Speaker must be 4Ω or higher.

Circuit Diagram of Music generator using ic UM66: 

Fig: Circuit Diagram of Song-Music generator using IC-UM66

UM66TXX series IC generate different songs-music, the song-music depends on the model of UM66TXX series IC’s. The song-music are listed below with model number.

Astable multivibrator-2 LED flashing circuit,2N3904,3.7V

Many of my friends asked me for automatic on off led circuit or  led flashing circuit so here I’m going to post a Astable multivibrator-2 LED flashing circuit.

Circuit diagram of Astable multivibrator with 2 LED:

Fig:  Astable multivibrator-2 LED flashing circuit Circuit diagram

It is a simple astable multivibrator circuit using 2LED (here i used red LED), two NPN small transistor 2N3904 for switching. Here other small NPN transistor can be used, including  2N4401, 2N2222 or PN2222. Supply voltage is +3.7V to +5V or if you want to supply a larger volt then add a required resistor series connected with  2 LED’s. I recommend to use +3.7V for best result . for +3.7V you can use a battery of  mobile phone.