Electronic Circuits and Diagram-Electronics Projects and Design

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…

Car Head Lights Turn Off Circuit Description This circuit when setup in a car automatically turns off the head light after a preset time after the ignition switch is turned off.So you can walk out easily from the dark garage in the light of your car. When the ignition switched on first the voltage from battery is fed to the relay through diode D1.When the ignition switch is turned off it produces a negative going pulse at the pin 2 that triggers the timer. The output of the IC goes high for the time set by R1  .This makes the…

Photo Switch Circuit using 555 IC Description This is a simple photo switch suitable for home and industrial purpose.The circuit switches on a relay when the light intensity falling on the sensor crosses the set limit. The circuit is based on a NE 555 and two transistors for driving the relay.The resistor R1  is adjusted such a way that under normal condition the voltage across the LDR is less than 1/3 the supply voltage.In this condition output of IC is high .This makes transistor Q1 on .Transistor Q2′s base is connected to collector of Q1.So  Q2 will be off keeping…

Automatic Wiper Control Description A continuously working wiper is a big problem when it is raining slightly.The wiper control given here makes the wiper to sweep at rates from 1S to 10 S. The circuit is build around an astable multivibrator using NE 555.Here the output at pin 3 remains high for a time period set by R2 ,and low for a time period set by R3.The low output pulse drives the transistor pair to drive the wiper motor to make one sweeping cycle and waits for next low pulse to arrive for next sweep.The high going pulse at pin…

Simple Radio Circuit Description This is a low cost simple radio circuit  based on op amp which can be used to listen to nearby stations. A simple op-amp radio basically consists of a crystal radio along with a fairly sensitive audio amplifier. The audio amplifier is able to receive strong stations around Los Angeles with a minimal 15 foot antenna. Stronger signals are always provided by longer antennas.But the main disadvantage is that in the case of long antennas the stronger signals provided may produce a noise as it could be heard in the background of the weaker signals. In…

Radio Collar Transmitter Description This is the circuit diagram of a radio transmitter suitable for fitting on radio collars.The circuit transmits a pulse in the FM between band 88MHz to 105Mhz , which can be adjusted.IC Ne 555 is wired as an astable multivibrator for producing the tone.L1 ,C3 and Q1 forms the modulator.Q2 performs the final power amplification. Notes For the inductor make 5 turns of .5 mm dia insulated copper wire on a standard ball pen refill.Remove the refill and make a tap at the center of coil.To vary transmission frequency experiment with number of turns.Careful! what ever…

Power Supply Circuit-40 Volts-2A Description. This is a power supply circuit diagram of 40Volts, that is able to deliver 2A current.This circuit is suitable for power amplifiers .Transistor TIP 42 A is used as a pass transistor to increase the current capabilities.Voltage regulator LM 317 is the heart of this circuit .Here the out put voltage is set to 40 V by R5 & R8.If you want any other out put voltage use a 10 K pot instead of R5 and adjust it. Parts List. R1_______________3R9 1 or 2W Resistor R2______________   22R  1/4W Resistor R3_______________6K8 1/4W Resistor R4_____________     220R  1/4W…

This article lists various types of audio amplifier circuits using Mosfet.We have tested all these circuits in our lab and we found all of them performing satisfactorily. Note: This article will be modified with new versions of Mosfet amplifier circuits in future;we shall notify new additions in our home page. This article contains following list of amplifier circuits using Mosfet. List of Circuits 1. 18 Watts Mosfet Amplifier 2. 10 Watt Mosfet Audio Amplifier 3. 50 Watt Mosfet Amplifier Circuit 1. 18 Watts Mosfet Audio Amplifier Description This circuit is an audio amplifier capable of delivering a decent output power…

Melody Generator Circuit Description Here is a simple melody generator circuit you can make using an IC.The  UM66 series are CMOS IC’s  designed for using in calling bell, phone and toys. It has a built in ROM programmed for playing music. The device has very low power consumption.Thanks for the CMOS technology.The melody will be available at pin3 of UM66 and here it is amplified by using Q1 to drive the speaker.Resistor R1 limits the base current of Q1 within the safe values.Capacitor C1 is meant for noise suppression. Notes Power supply  must be between 1.5V & 4.5V .Do not…