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Simple 555 Timer Circuits & Projects

555 timer is an industrial standard IC existing from early days of IC. Its name is derived from three 5K ohm resistors ,connected in series used in it.The timer IC can produce  required waveform accurately.


555 timer was first introduced by signetics corporation in 1971 as SE555/NE555. It is a affordable, stable and user friendly IC in application such as monostable and bi stable. Here is the list of 40 555 timer circuits that can help you in understanding 555 timer functions.First five circuits explains about 555 timer and its different modes.

555 timer

List of Simple 555 Timer Circuits and Projects

  • Understanding 555 Timer: Here is the article explaining about the 555 timer .Different modes ,pin configuration, applications of the timer are also explained.
  • Astable Multivibrator Using 555 Timer: Astable mode is also called free running oscillator.IN this state 555 timer can trigger between two states without applying between any external triggering. This article explains the working of timer in this mode.
  • Monostable Multi vibrator using 555 Timer: In monostable mode 555 timer changes its state when only external trigger is applied. This article explains the working of this mode.
  • How 555 Timer IC Testing Circuit Works?: This article explains the working of a 555 timer IC tester.
  • 555 Timer as Schmitt Trigger: Here the 555 timer is used as a Schmitt trigger. Schmitt trigger is a regenerative comparator. It compares the input voltage with the two reference voltages and produces an equivalent voltage at the output.
  • Screaming Siren Circuit: Screaming Siren can be used as an Alert signal. Because of its ear piercing and irritating sound it can get immediate attention. The circuit shown here is build using a 555 timer circuit.
  • TV Transmitter Circuit:The TV Transmitter circuit designed here can transmit audio and video signals. This circuit amplifies and transmits the signals. Audio signals are frequency modulated and video signals are PAL modulated.
  • LC Meter Circuit using 555 Timer: The LC meter circuit shown here will measure the value of a reactive element like capacitor or an inductor. This circuit is designed using 555 timer IC.
  • Frequency Counter Circuit: This project shows a frequency measuring circuit. The two 555 timers are operated in two modes. One in astable mode and another one in mono stable mode. The timer in astable mode generates the pulses and these are fed to a counter. Timer in mono stable mode is used a timing signal. Thus the number of pulses generated in one sec can be measured using logic. Go through the article for more information.
  • High and Low Voltage Cutoff with Delay and Alarm: The circuit shown here gives protection to the electrical equipment. When there is any abnormal voltage (either high or low) .This circuit turns of the supply and produces and alarm as an indication. It also produces sound when it resumes.


  • Super sensitive intruder Alarm: This circuit shows an intruder alarm using 555 timer. The simple circuit shown here will produce an alarm when any intruder is detected. Intruder is detected using an op-amp.
  • TV Remote Jammer Circuit: Here this circuit shows a TV remote jammer circuit using 555 timer IC. This circuit produces a continuous signals that confuses the TV remote. Thus the TV signals were jammed.
  • Ding Dong Sound Generator Circuit: Here is the circuit for producing Ding Dong sound. This circuit can be used as a door bell.
  • Police Lights using 555 Timer: The circuit shown here simulates the police car lights. In this red LED’s are flashed for three times and blue Led’s are flashed for three times alternately. This flashing is performed continuously.
  • Bike Turning Signal Circuit: Here is the circuit showing bike turning signal.555 timer plays a main role in this circuit. It is operated in astable mode. Two sets of led’s were used for indicating left and right signal.
  • Automatic Changeover Switch: The change over switch can act as an inverter. But here the DC operated load is switched from DC to AC to DC power supply in case of DC power failure.
  • Reverse Parking Sensor Circuit: Reverse parking sensor circuit helps the driver in parking the vehicle safely. This circuit indicates the distance using three LEDs.
  • Dummy Alarm Circuit: As the name indicates this alarm flashes LEDs for every 5 second instead of producing sound.
  • Low Power Audio Amplifier using 555 Timer: Here a low power audio amplifier circuit is designed using 555 timer IC. It can output a current of 200mA. This can drive a small loud speaker.
  • Toy Organ Circuit using 555 Timer IC: The toy organ circuit can also called as toy piano circuit. Here in this circuit there are 5 push button. Pressing them in a order will produce music similar to a piano.
  • Digital Stopwatch Circuit: The digital sop watch shown here will count 60 seconds. This works on the principle of two stage counter. The 555 timer here is used for producing the clock pulses. These clock pulses were given to the counter circuits for counting purpose.
  • 3X3X3 LED Cube Circuit: Here a simple 3x3x3 LED cube circuit is designed.The LED cube here is controlled a 555 timer.
  • Air Flow Detector Circuit: A simple air flow detector is designed here. Air flow detection is used in many applications like to check the amount of fuel to be added to an engine or to measure the contamination etc. Air flow is detected using variation of resistance with temperature ,air acting a insulator.
  • Electronic Mosquito Repellent Circuit: Here an electronic mosquito repellent circuit is designed. The circuit shown here uses 555 timer as a main component.
  • Police Siren Circuit using NE555 Timer: This circuit produces a police siren sound. It uses two 555 timer ICs in astable mode.
  • Audio Equalizer Circuit: The audio equalizer circuit can change the tune of the sound. It can produce different musical sounds from a single melody.
  • 9 Way Clap Switch Circuit: This circuit shows a clap switch circuit. Here this clap switch can generate 9 different patterns. Hence the name 9 way clap switch. The 555 timer is used in mono stable mode and these pulses are applied to IC CD 7490 decade counter.
  • LED Running Lights Circuit: Led running lights circuit can also be called as knight rider circuit. This circuit uses 555 timer and CD4017 counter. These lights can be used to place in front of the car .
  • Touch ON and OFF Switch Circuit: Here is the ON and OFF switch circuit. This circuit can be used to switch the loads without moving from one place by simply touching the circuit.555 timer is used on monostable mode here.
  • Automatic Plant Irrigation System: This system shows an automatic plant irrigation system. It automatically switches the relay by measuring the moisture of the soil. Soil moisture is measured using soil moisture sensor. Two 55 timers were used in this circuit.
  • Simple LED Blinking Circuits: This article shows two led blinking circuits. One is a flasher and the other one is a bi colour led dancing lights.
  • Simple Fire Alarm Circuits at Low Cost: Here is the article showing Fire Alarm circuits at very cost. It shows four different circuits using simple components along with circuit diagram and its working.
  • IR Remote Control Switch: This project shows the controlling of home appliances using IR remote. There are two circuits one used as a transmitter and the other one used as a receiver.555 timer is used in transmitter circuit.
  • Car Parking Guard Circuit Using Infrared Sensor: Car parking guide will help the driver in detecting the obstacle in the path of parking. Infrared sensor is used to detect the obstacle in the path.
  • PWM LED Dimmer Using NE555: Here a LED dimmer circuit using 555 timer is proposed. Dimming operation is done using PWM produced from 555 timer.
  • Speed Control of DC Motor Using Pulse Width Modulation: This article shows the speed controlling of a DC motor using WM.Here PWM is generated using 555 timer.
  • Continuity tester With Melody: Here a continuity tester circuit is designed. It produces a melody sound when there no continuity in the circuit.
  • Panic Alarm Is An Alarm Circuit: Panic Alarm is an alarm circuit built using 555 timer IC. This alarm pressed at the panic situations can alert the neighbours.
  • Unbiased Electronic Dice With Leds: Here an electronic digital dice circuit is proposed. This circuit is accurate for playing the game and get exact output.
  • Speed Controller Using 555: Here is a DIY article showing the Speed control of small DC motor using 555 timer.
  • How To Make Simple Clap Switch: Circuit, Working?: Here is a simple clap switch circuit made from 555 timer.
  • Mobile controlled Home Appliances without Microcontroller: Here is the project for controlling home appliances using mobile without any microcontroller. Although the main role in this project is played by DTMF decoder .555 can be used to control the appliances. Go through the project for more information.

We would like to suggest you to check below some good list of projects

Feel free to comment if you have any new list, we will try to put it here.