Electronic Circuits and Diagram-Electronics Projects and Design

Musical Light Chaser Description Here is a simple state of the art musical chaser circuit that can be used in discotheques or even at home if you are a little music crazy . The working of the circuit is straight forward ,the condenser mic pickup the sound and Q1 amplifies it.This signal is fed to clock input of IC1 ,CD 4016. The IC is wired in divide by ten mode. The out put of IC1 is given to clock input of IC2, CD4016.The out puts of IC 2  shown in the right side of IC2  in circuit diagram will run…

PWM Motor Speed Control Description Here is a simple PWM motor speed controller circuit that can be used for varying the speed of low power DC motors . The variation in speed is achieved by varying the duty cycle of the pulse supplied to drive the motor. Of the two gates of IC CD40106B , N1 is wired as an inverting Schmitt Trigger astable multi vibrator for producing pulses and N2 as an inverting buffer to drive the transistor during positive cycles at base. The duty cycle is set from resistor R2. R1 limits the base current of transistor SL…

Description. A dual tone train horn simulator circuit can be made using two NE 555 timers connected in cascade.Here instead of using two NE 555 timers a single NE 556 timer is used which is a nothing but two 555′s in one package and each timers work independently.Switch S1 can be used to start the horn.The circuit is simple and low cost but works greatly. Circuit Diagram & Parts List. Notes Use a 9V DC power supply or battery for this circuit. Assemble the circuit on a good quality PCB or common board.Constructing a bread board prototype is recommended. We…

Doorbell Circuit Description Here is a simple and easy to build doorbell circuit using IC UM 66.The  details of UM 66  is given in the older post “Melody Generator using UM 66″. This is a slight modification of that circuit.In the previous circuit you have to keep the switch pressed for making the IC play the full music.Here if once the push button is pressed C1 is charged and the transistor Q2 will keep the IC playing the music till it ends.The time for the IC to play depends on discharging time of C1  which can be set by R1.Set…

Seven Segment Counter Display Circuit Description Here is the circuit diagram of a seven segment counter based on the counter IC CD 4033.This circuit can be used in conjunction with various circuits where a counter to display the progress  adds some more attraction. IC NE 555 is wired as an astable multivibrator for triggering the CD 4033.For each pulse the out put of CD 4033 advances by one count.The output of CD 4033 is displayed by the seven segment LED display LT543.Switch S1 is used to initiate the counting.Diode D1 prevents the risk of accidental polarity reversal. Seven Segment Circuit…

Car Battery Voltmeter Circuit Description This is a very useful circuit which when installed on your car gives the voltage of you car battery in a LED dot display form.The circuit is based on four comparators made of quad op amp LM324.The inverting inputs of IC are kept at at reference voltages 5.6V,5.2V,4.8V,4.4V respectively at pins 2,6,9,13 by resistors ,R3,R4,R5,R6.The battery voltage is directly fed to the pin inverting input through the voltage divider arrangement using R1 and R7.When there is variation in the input supply the out put of each op amp goes high accordingly as they are wired…

Power Amplifier Circuit – 25 Watts Description Here is the diagram of a 25 Watt power amplifier circuit made of  TDA 2009 IC.TDA 2009 has two channels each rating 12.5 watts on 4 Ohm load.Here the two channels are bridged to get a single out put channel weighting 25 W. TDA 2009 IC has also built in features such as short circuit protection,thermal protection, overload protection etc using very low external components.The most interesting factor I see about this IC is that it require no dual supply. Power Amplifier Circuit Diagram and Power Supply Circuit Schematic   Notes Do not…

Metal Detector Circuit Description This is the circuit diagram of a low cost metal detector using a single transistor circuit and an old pocket radio.This is nothing but a Colpitts oscillator working in the medium band frequency and a radio tuned to the same frequency.First the radio and the circuit are placed close.Then the radio is tuned so that there is no sound from radio.In this condition the radio and the circuit will be in same frequency and same frequencies beat off to produce no sound.This is the set up.When the metal detector circuit is placed near to a metal…

Lamp Flasher using NE 555 Description This is the circuit diagram of lamp flasher operated from mains. By this you can flash up to 200 Watt lamps at rates determined by you. IC NE555 is wired as an astable multivibrator for producing the pulses for flashing the lamp. The flashing rate can be set by the value of resistors R2 & R3. Diodes D1 & D2 provides a half wave rectified regulated supply for the IC. Transistor T1 is used to drive triac and triac BT136 for driving the load. Resistor R4 limits the base current of Q1. Flashing Circuit…

Touch Switch Circuit using NE 555 Description This is the circuit diagram of a small touch plate controller using IC NE 555 .This circuit is ideally useful for making touch operated doorbells, buzzers,toys etc which when touched on the touch plate operates the relay for a preset time and the turns off automatically. This circuit is realized by utilizing the high input impedance of trigger pin of the 555 IC.When  the IC is triggered by the induced voltage of human body the output goes high for a time determined by R1 and C1.The transistor is used to drive the relay.The…